130-442: The Sinclair Sovereign was a high-end calculator introduced by Clive Sinclair 's company Sinclair Radionics in 1976. It was an attempt to escape from the unprofitable low end of the market, and one of the last calculators Sinclair produced. Made with a case of pressed steel that a variety of finishes, it cost between £30 and £60 at a time when other calculators could be purchased for under £5 . A number of factors meant that
260-568: A Design Council award, and there are examples of the Sovereign in the Museum of Modern Art in New York . It had a Mostek MK50321N main integrated circuit and a small memory register , a LED display, and could perform a variety of a number of basic mathematical operations besides four-function arithmetic. The Sovereign was one of the last calculators produced during Sinclair's foray into
390-407: A button can perform multi-function working with key combinations . Calculators usually have liquid-crystal displays (LCD) as output in place of historical light-emitting diode (LED) displays and vacuum fluorescent displays (VFD); details are provided in the section Technical improvements . Large-sized figures are often used to improve readability; while using decimal separator (usually
520-399: A calculator could be made using just a few chips of low power consumption, allowing portable models powered from rechargeable batteries. The first handheld calculator was a 1967 prototype called Cal Tech , whose development was led by Jack Kilby at Texas Instruments in a research project to produce a portable calculator. It could add, multiply, subtract, and divide, and its output device
650-404: A cavity perpendicular to the draw direction, to form overhanging part features. When the mould is opened, the slides are pulled away from the plastic part by using stationary “angle pins” on the stationary mould half. These pins enter a slot in the slides and cause the slides to move backward when the moving half of the mould opens. The part is then ejected and the mould closes. The closing action of
780-684: A development from the "Cal-Tech" project. It had no traditional display; numerical output was on thermal paper tape. Sharp put in great efforts in size and power reduction and introduced in January 1971 the Sharp EL-8 , also marketed as the Facit 1111, which was close to being a pocket calculator. It weighed 1.59 pounds (721 grams), had a vacuum fluorescent display , rechargeable NiCad batteries, and initially sold for US$ 395. However, integrated circuit development efforts culminated in early 1971 with
910-566: A different colour, is injection-moulded into those spaces. Pushbuttons and keys , for instance, made by this process have markings that cannot wear off, and remain legible with heavy use. Manufacturers go to great lengths to protect custom moulds due to their high average costs. The perfect temperature and humidity level is maintained to ensure the longest possible lifespan for each custom mould. Custom moulds, such as those used for rubber injection moulding, are stored in temperature and humidity controlled environments to prevent warping. Tool steel
1040-609: A full single chip calculator IC for the Monroe Royal Digital III calculator. Pico was a spinout by five GI design engineers whose vision was to create single chip calculator ICs. Pico and GI went on to have significant success in the burgeoning handheld calculator market. The first truly pocket-sized electronic calculator was the Busicom LE-120A "HANDY", which was marketed early in 1971. Made in Japan, this
1170-470: A hopper into a heated barrel with a reciprocating screw. Upon entrance to the barrel, the temperature increases and the Van der Waals forces that resist relative flow of individual chains are weakened as a result of increased space between molecules at higher thermal energy states. This process reduces its viscosity , which enables the polymer to flow with the driving force of the injection unit. The screw delivers
1300-483: A host of materials mainly including metals (for which the process is called die-casting ), glasses , elastomers , confections , and most commonly thermoplastic and thermosetting polymers. Material for the part is fed into a heated barrel, mixed (using a helical screw), and injected into a mould cavity , where it cools and hardens to the configuration of the cavity. After a product is designed, usually by an industrial designer or an engineer , moulds are made by
1430-433: A large variation in dimensions from cycle-to-cycle. More commonly used now is scientific or decoupled moulding, a method pioneered by RJG Inc. In this the injection of the plastic is "decoupled" into stages to allow better control of part dimensions and more cycle-to-cycle (commonly called shot-to-shot in the industry) consistency. First the cavity is filled to approximately 98% full using velocity (speed) control. Although
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#17327904094851560-492: A material hopper, an injection ram or screw-type plunger, and a heating unit. Also known as platens, they hold the moulds in which the components are shaped. Presses are rated by tonnage, which expresses the amount of clamping force that the machine can exert. This force keeps the mould closed during the injection process. Tonnage can vary from less than 5 tons to over 9,000 tons, with the higher figures used in comparatively few manufacturing operations. The total clamp force needed
1690-502: A mould-maker (or toolmaker) from metal , usually either steel or aluminium , and precision-machined to form the features of the desired part. Injection moulding is widely used for manufacturing a variety of parts, from the smallest components to entire body panels of cars. Advances in 3D printing technology, using photopolymers that do not melt during the injection moulding of some lower-temperature thermoplastics, can be used for some simple injection moulds. Injection moulding uses
1820-554: A new plastic layer to form around the first part. This is often referred to as overmoulding. This system can allow for production of one-piece tires and wheels. Moulds for highly precise and extremely small parts from micro injection molding requires extra care in the design stage, as material resins react differently compared to their full-sized counterparts where they must quickly fill these incredibly small spaces, which puts them under intense shear strains. Two-shot, double-shot or multi-shot moulds are designed to "overmould" within
1950-485: A pocket calculator. Launched in early 1972, it was unlike the other basic four-function pocket calculators then available in that it was the first pocket calculator with scientific functions that could replace a slide rule . The $ 395 HP-35 , along with nearly all later HP engineering calculators, uses reverse Polish notation (RPN), also called postfix notation. A calculation like "8 plus 5" is, using RPN, performed by pressing 8 , Enter↑ , 5 , and + ; instead of
2080-428: A point rather than a comma ) instead of or in addition to vulgar fractions . Various symbols for function commands may also be shown on the display. Fractions such as 1 ⁄ 3 are displayed as decimal approximations , for example rounded to 0.33333333 . Also, some fractions (such as 1 ⁄ 7 , which is 0.14285714285714 ; to 14 significant figures ) can be difficult to recognize in decimal form; as
2210-437: A result, many scientific calculators are able to work in vulgar fractions or mixed numbers . Calculators also have the ability to save numbers into computer memory . Basic calculators usually store only one number at a time; more specific types are able to store many numbers represented in variables . Usually these variables are named ans or ans(0). The variables can also be used for constructing formulas . Some models have
2340-420: A series of separate identical seven-segment displays to build a metering circuit, for example. If the numeric quantity were stored and manipulated as pure binary, interfacing to such a display would require complex circuitry. Therefore, in cases where the calculations are relatively simple, working throughout with BCD can lead to a simpler overall system than converting to and from binary. (For example, CDs keep
2470-404: A single moulding cycle and must be processed on specialised injection moulding machines with two or more injection units. This process is actually an injection moulding process performed twice and therefore can allow only for a much smaller margin of error. In the first step, the base colour material is moulded into a basic shape, which contains spaces for the second shot. Then the second material,
2600-410: A small shot weight and fills gradually until the mould is 95 to 99% full. Once they achieve this, they apply a small amount of holding pressure and increase holding time until gate freeze off (solidification time) has occurred. Gate freeze off time can be determined by increasing the hold time, and then weighing the part. When the weight of the part does not change, the gate has frozen and no more material
2730-422: A solidified thermoset component. After the part has solidified, valves close to isolate the injection system and chemical precursors , and the mould opens to eject the moulded parts. Then, the mould closes and the process repeats. Pre-moulded or machined components can be inserted into the cavity while the mould is open, allowing the material injected in the next cycle to form and solidify around them. This process
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#17327904094852860-406: A special-purpose machine that has three parts: the injection unit, the mould and the clamp. Parts to be injection-moulded must be very carefully designed to facilitate the moulding process; the material used for the part, the desired shape and features of the part, the material of the mould, and the properties of the moulding machine must all be taken into account. The versatility of injection moulding
2990-418: A timely manner, chemical crosslinking may occur causing the screw and check valves to seize and potentially damaging the injection moulding machine. Injection moulding consists of the high pressure injection of the raw material into a mould, which shapes the polymer into the desired form. Moulds can be of a single cavity or multiple cavities. In multiple cavity moulds, each cavity can be identical and form
3120-482: Is 38–45 on the Rockwell-C scale . Hardened steel moulds are heat treated after machining; these are by far superior in terms of wear resistance and lifespan. Typical hardness ranges between 50 and 60 Rockwell-C (HRC). Aluminium moulds can cost substantially less, and when designed and machined with modern computerised equipment can be economical for moulding tens or even hundreds of thousands of parts. Beryllium copper
3250-469: Is a function of the resin being used, and can be relatively predictable. To prevent spikes in pressure, the process normally uses a transfer position corresponding to a 95–98% full cavity where the screw shifts from a constant velocity to a constant pressure control. Often injection times are well under 1 second. Once the screw reaches the transfer position the packing pressure is applied, which completes mould filling and compensates for thermal shrinkage, which
3380-419: Is common in electronic systems where a numeric value is to be displayed, especially in systems consisting solely of digital logic, and not containing a microprocessor. By employing BCD, the manipulation of numerical data for display can be greatly simplified by treating each digit as a separate single sub-circuit. This matches much more closely the physical reality of display hardware—a designer might choose to use
3510-412: Is dealt with in the next section.}) Some extremely high production volume moulds (like those for bottle caps) can have over 128 cavities. In some cases, multiple cavity tooling moulds a series of different parts in the same tool. Some toolmakers call these moulds family moulds, as all the parts are related—e.g., plastic model kits. Some moulds allow previously moulded parts to be reinserted to allow
3640-452: Is determined by the projected area of the part being moulded. This projected area is multiplied by a clamp force of from 1.8 to 7.2 tons for each square centimetre of the projected areas. As a rule of thumb, 4 or 5 tons/in can be used for most products. If the plastic material is very stiff, it requires more injection pressure to fill the mould, and thus more clamp tonnage to hold the mould closed. The required force can also be determined by
3770-436: Is facilitated by this breadth of design considerations and possibilities. Injection moulding is used to create many things such as wire spools , packaging , bottle caps , automotive parts and components, toys, pocket combs , some musical instruments (and parts of them), one-piece chairs and small tables, storage containers, mechanical parts (including gears), and most other plastic products available today. Injection moulding
3900-401: Is immersed in paraffin oil (kerosene). A voltage applied between tool and mould causes spark erosion of the mould surface in the inverse shape of the electrode. The number of cavities incorporated into a mould directly correlate in moulding costs. Fewer cavities require far less tooling work, so limiting the number of cavities lowers initial manufacturing costs to build an injection mould. As
4030-443: Is injected into the part. Gate solidification time is important, as this determines cycle time and the quality and consistency of the product, which itself is an important issue in the economics of the production process. Holding pressure is increased until the parts are free of sinks and part weight has been achieved. Injection moulding is a complex technology with possible production problems. They can be caused either by defects in
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4160-424: Is known as insert moulding and allows single parts to contain multiple materials. This process is often used to create plastic parts with protruding metal screws so they can be fastened and unfastened repeatedly. This technique can also be used for In-mould labelling and film lids may also be attached to moulded plastic containers. A parting line , sprue , gate marks, and ejector pin marks are usually present on
4290-430: Is maintained to compensate for material shrinkage. In the next step, the screw turns, feeding the next shot to the front screw. This causes the screw to retract as the next shot is prepared. Once the part is sufficiently cool, the mould opens and the part is ejected. Traditionally, the injection portion of the moulding process was done at one constant pressure to fill and pack the cavity. This method, however, allowed for
4420-473: Is needed to fit all the desired functions in the limited memory space available in the calculator chip , with acceptable calculation time. The first known tools used to aid arithmetic calculations were: bones (used to tally items), pebbles, and counting boards , and the abacus , known to have been used by Sumerians and Egyptians before 2000 BC. Except for the Antikythera mechanism (an "out of
4550-405: Is notably different from the layout of telephone Touch-Tone keypads which have the 1 - 2 - 3 keys on top and 7 - 8 - 9 keys on the third row. In general, a basic electronic calculator consists of the following components: Clock rate of a processor chip refers to the frequency at which the central processing unit (CPU) is running. It is used as an indicator of
4680-428: Is often used. Mild steel, aluminium, nickel or epoxy are suitable only for prototype or very short production runs. Modern hard aluminium (7075 and 2024 alloys) with proper mould design, can easily make moulds capable of 100,000 or more part life with proper mould maintenance. Moulds are built through two main methods: standard machining and EDM . Standard machining, in its conventional form, has historically been
4810-417: Is quite high for thermoplastics relative to many other materials. The packing pressure is applied until the gate (cavity entrance) solidifies. Due to its small size, the gate is normally the first place to solidify through its entire thickness. Once the gate solidifies, no more material can enter the cavity; accordingly, the screw reciprocates and acquires material for the next cycle while the material within
4940-449: Is repeated. For a two-shot mould, two separate materials are incorporated into one part. This type of injection moulding is used to add a soft touch to knobs, to give a product multiple colours, or to produce a part with multiple performance characteristics. For thermosets, typically two different chemical components are injected into the barrel. These components immediately begin irreversible chemical reactions that eventually crosslinks
5070-610: Is the first calculator in the world which includes the square root function. Later that same year were released the ELKA 22 (with a luminescent display) and the ELKA 25, with an built-in printer. Several other models were developed until the first pocket model, the ELKA 101 , was released in 1974. The writing on it was in Roman script , and it was exported to western countries. The first desktop programmable calculators were produced in
5200-417: Is the most common modern method of manufacturing plastic parts; it is ideal for producing high volumes of the same object. Injection moulding uses a ram or screw-type plunger to force molten plastic or rubber material into a mould cavity; this solidifies into a shape that has conformed to the contour of the mould. It is most commonly used to process both thermoplastic and thermosetting polymers , with
5330-423: Is used in areas of the mould that require fast heat removal or areas that see the most shear heat generated. The moulds can be manufactured either by CNC machining or by using electrical discharge machining processes. The mould consists of two primary components, the injection mould (A plate) and the ejector mould (B plate). These components are also referred to as moulder and mouldmaker . Plastic resin enters
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5460-402: Is used to fill the mould cavity, compensate for shrinkage, and provide a cushion (approximately 10% of the total shot volume, which remains in the barrel and prevents the screw from bottoming out) to transfer pressure from the screw to the mould cavity. When enough material has gathered, the material is forced at high pressure and velocity into the part forming cavity. The exact amount of shrinkage
5590-505: The Sinclair Cambridge . Clive Sinclair had assumed that people would prefer attractive illuminated LED displays to LCD displays, which incidentally also required more expensive CMOS chips. However, his calculators were designed with the assumption they would be turned off between calculations, which did not prove to be the case. Advertisements suggested that the batteries would last "about a year" under normal use, but in reality
5720-482: The 1940s because World War II created a huge demand for inexpensive, mass-produced products. In 1946, American inventor James Watson Hendry built the first screw injection machine, which allowed much more precise control over the speed of injection and the quality of articles produced. This machine also allowed material to be mixed before injection, so that coloured or recycled plastic could be added to virgin material and mixed thoroughly before being injected. In
5850-495: The 1970s, Hendry went on to develop the first gas-assisted injection moulding process, which permitted the production of complex, hollow articles that cooled quickly. This greatly improved design flexibility as well as the strength and finish of manufactured parts while reducing production time, cost, weight and waste. By 1979, plastic production overtook steel production, and by 1990, aluminium moulds were widely used in injection moulding. Today, screw injection machines account for
5980-547: The 1970s, especially after the Intel 4004 , the first microprocessor , was developed by Intel for the Japanese calculator company Busicom . Modern electronic calculators vary from cheap, give-away, credit-card-sized models to sturdy desktop models with built-in printers. They became popular in the mid-1970s as the incorporation of integrated circuits reduced their size and cost. By the end of that decade, prices had dropped to
6110-515: The ANITA was superseded in June 1963 by the U.S. manufactured Friden EC-130, which had an all-transistor design, a stack of four 13-digit numbers displayed on a 5-inch (13 cm) cathode-ray tube (CRT), and introduced Reverse Polish Notation (RPN) to the calculator market for a price of $ 2200, which was about three times the cost of an electromechanical calculator of the time. Like Bell Punch, Friden
6240-598: The Autumn of 1971, with four functions and an eight-digit red LED display, for US$ 240 , while in August 1972 the four-function Sinclair Executive became the first slimline pocket calculator measuring 5.4 by 2.2 by 0.35 inches (137.2 mm × 55.9 mm × 8.9 mm) and weighing 2.5 ounces (71 g). It retailed for around £79 ( US$ 194 at the time). By the end of the decade, similar calculators were priced less than £5 ($ 6.85). Following protracted development over
6370-696: The Mk VII for continental Europe and the Mk VIII for Britain and the rest of the world, both for delivery from early 1962. The Mk VII was a slightly earlier design with a more complicated mode of multiplication, and was soon dropped in favour of the simpler Mark VIII. The ANITA had a full keyboard, similar to mechanical comptometers of the time, a feature that was unique to it and the later Sharp CS-10A among electronic calculators. The ANITA weighed roughly 33 pounds (15 kg) due to its large tube system. Bell Punch had been producing key-driven mechanical calculators of
6500-439: The Sovereign was not a commercial success, including the cost, high import levies on components, competition from cheaper calculators manufactured abroad, and the development of more power-efficient designs using liquid-crystal displays . Though it came with a five-year guarantee, issues such as short battery life limited its usefulness. The company moved on to producing computers soon afterwards. The design by John Pemberton won
6630-582: The Sovereign was sold with a "full and unconditional" five year guarantee. The Sovereign came in satin chrome and gold-plated models, with leather pouches and fitted wooden cases. It had an 8-digit seven-segment display that used red light-emitting diodes , with a decimal point to the right of each digit that could be illuminated as necessary. Power was provided by two 1.35 mercury button cells . The Sovereign measured 36 by 141 by 12 millimetres (1.42 in × 5.55 in × 0.47 in), which made it small and sleek compared to other calculators of
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#17327904094856760-493: The ability to extend memory capacity to store more numbers; the extended memory address is termed an array index. Power sources of calculators are batteries , solar cells or mains electricity (for old models), turning on with a switch or button. Some models even have no turn-off button but they provide some way to put off (for example, leaving no operation for a moment, covering solar cell exposure, or closing their lid ). Crank -powered calculators were also common in
6890-432: The ability to multiply by a fixed constant. With an eight-digit display, the calculator could display positive numbers between 0.0000001 and 99,999,999, and negative numbers between -0.000001 and -9,999,999. Calculators of the time tended to have displays of between 3 and 12 digits, as reducing the number of digits was an effective way of reducing the cost of the calculator. A number outside that range leads to an overflow, and
7020-413: The adding machine as a means of completing this operation. There is a debate about whether Pascal or Shickard should be credited as the known inventor of a calculating machine due to the differences (like the different aims) of both inventions. Schickard and Pascal were followed by Gottfried Leibniz who spent forty years designing a four-operation mechanical calculator, the stepped reckoner , inventing in
7150-560: The algebraic infix notation : 8 , + , 5 , = . It had 35 buttons and was based on Mostek Mk6020 chip. The first Soviet scientific pocket-sized calculator the "B3-18" was completed by the end of 1975. In 1973, Texas Instruments (TI) introduced the SR-10 , ( SR signifying slide rule ) an algebraic entry pocket calculator using scientific notation for $ 150. Shortly after the SR-11 featured an added key for entering pi (π). It
7280-400: The article using pins, sleeves, strippers, etc., may cause undesirable impressions or distortion, so care must be taken when designing the mould. The standard method of cooling is passing a coolant (usually water) through a series of holes drilled through the mould plates and connected by hoses to form a continuous pathway. The coolant absorbs heat from the mould (which has absorbed heat from
7410-639: The calculator market that had started with the Sinclair Executive in September 1972. The Executive had retailed for £80 when introduced, but in little over a year it was possible to purchase a Sinclair calculator for £20 and by November 1976 a model was available for £4.95 . Cheaper calculators with liquid-crystal displays instead of light-emitting diodes were becoming more popular, and had much longer battery lives of months or years. Such calculators were available for well under £10 , with all
7540-528: The calculator market was due in part to technological development leading to smaller and cheaper components, which put heavy pressure on profit margins. An import levy of up to 17.5% was placed on components, but the duty for calculators imported from Japan or Hong Kong could be as little as 5%, making it unprofitable to produce calculators in the UK. Sinclair also had some problems with the reliability of earlier calculators that had adversely affected its reputation, but
7670-419: The chemical precursors are minimised in the injection unit. The residence time can be reduced by minimising the barrel's volume capacity and by maximising the cycle times. These factors have led to the use of a thermally isolated, cold injection unit that injects the reacting chemicals into a thermally isolated hot mould, which increases the rate of chemical reactions and results in shorter time required to achieve
7800-415: The comptometer type under the names "Plus" and "Sumlock", and had realised in the mid-1950s that the future of calculators lay in electronics. They employed the young graduate Norbert Kitz, who had worked on the early British Pilot ACE computer project, to lead the development. The ANITA sold well since it was the only electronic desktop calculator available, and was silent and quick. The tube technology of
7930-453: The conventional process description above, there are several important moulding variations including, but not limited to: A more comprehensive list of injection moulding processes may be found here: [1] Like all industrial processes, injection molding can produce flawed parts, even in toys. In the field of injection moulding, troubleshooting is often performed by examining defective parts for specific defects and addressing these defects with
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#17327904094858060-410: The core and cavity of moulds further influences cost. Rubber injection moulding process produces a high yield of durable products, making it the most efficient and cost-effective method of moulding. Consistent vulcanisation processes involving precise temperature control significantly reduces all waste material. Usually, the plastic materials are formed in the shape of pellets or granules and sent from
8190-506: The cost of design, fabrication , processing , and quality monitoring. The skillful mould and part designer positions these aesthetic detriments in hidden areas if feasible. In 1846 the British inventor Charles Hancock, a relative of Thomas Hancock , patented an injection molding machine. American inventor John Wesley Hyatt , together with his brother Isaiah, patented one of the first injection moulding machines in 1872. This machine
8320-538: The course of two years including a botched partnership with Texas Instruments, Eldorado Electrodata released five pocket calculators in 1972. One called the Touch Magic was "no bigger than a pack of cigarettes" according to Administrative Management . The first Soviet Union made pocket-sized calculator, the Elektronika B3-04 was developed by the end of 1973 and sold at the start of 1974. One of
8450-435: The design of the mould or the characteristics of the process itself. Trials are often performed before full production runs in an effort to predict defects and determine the appropriate specifications to use in the injection process. When filling a new or unfamiliar mould for the first time, where shot size for that mould is unknown, a technician/tool setter may perform a trial run before a full production run. They start with
8580-424: The direction that the mould opens, unless parts of the mould are designed to move from between such overhangs when the mould opens using components called Lifters. Sides of the part that appear parallel with the direction of draw (the axis of the cored position (hole) or insert is parallel to the up and down movement of the mould as it opens and closes) are typically angled slightly, called draft, to ease release of
8710-428: The early computer era. The following keys are common to most pocket calculators. While the arrangement of the digits is standard, the positions of other keys vary from model to model; the illustration is an example. The arrangement of digits on calculator and other numeric keypads with the 7 - 8 - 9 keys two rows above the 1 - 2 - 3 keys is derived from calculators and cash registers . It
8840-493: The eve of the industrial revolution made large scale production of more compact and modern units possible. The Arithmometer , invented in 1820 as a four-operation mechanical calculator, was released to production in 1851 as an adding machine and became the first commercially successful unit; forty years later, by 1890, about 2,500 arithmometers had been sold plus a few hundreds more from two arithmometer clone makers (Burkhardt, Germany, 1878 and Layton, UK, 1883) and Felt and Tarrant,
8970-406: The final part. None of these features are typically desired, but are unavoidable due to the nature of the process. Gate marks occur at the gate that joins the melt-delivery channels (sprue and runner) to the part forming cavity. Parting line and ejector pin marks result from minute misalignments, wear, gaseous vents, clearances for adjacent parts in relative motion, and/or dimensional differences of
9100-467: The first Japanese one) was the Casio (AL-1000) produced in 1967. It featured a nixie tubes display and had transistor electronics and ferrite core memory. The Monroe Epic programmable calculator came on the market in 1967. A large, printing, desk-top unit, with an attached floor-standing logic tower, it could be programmed to perform many computer-like functions. However, the only branch instruction
9230-492: The first direct multiplication machine in 1834: this was also the second key-driven machine in the world, following that of James White (1822). It was not until the 19th century and the Industrial Revolution that real developments began to occur. Although machines capable of performing all four arithmetic functions existed prior to the 19th century, the refinement of manufacturing and fabrication processes during
9360-492: The first low-cost calculators was the Sinclair Cambridge , launched in August 1973. It retailed for £29.95 ($ 41.03), or £5 ($ 6.85) less in kit form, and later models included some scientific functions. The Sinclair calculators were successful because they were far cheaper than the competition; however, their design led to slow and less accurate computations of transcendental functions (maximum three decimal places of accuracy). Meanwhile, Hewlett-Packard (HP) had been developing
9490-407: The first soluble forms of cellulose acetate in 1903, which was much less flammable than cellulose nitrate . It was eventually made available in a powder form from which it was readily injection moulded. Arthur Eichengrün developed the first injection moulding press in 1919. In 1939, Arthur Eichengrün patented the injection moulding of plasticised cellulose acetate. The industry expanded rapidly in
9620-490: The functionality of the more expensive models. The impossibility of selling "simple" calculators profitably led Sinclair to introduce models such as the Cambridge Scientific , introduced in August 1975 at a price of £29.95 . The Sovereign, released in 1976, represented an attempt to move upmarket in an increasingly saturated market . In December 1976, the chrome plated version of the Sovereign cost £30 and
9750-579: The gold-plated version £60 , including VAT , but profit margins on the Sovereign were so small that Sinclair ended up selling the Sovereign at a loss, and it was not a commercial success. The Sovereign was made in England, like every other Sinclair calculator except the President . Sinclair would shortly stop producing calculators and instead focus on computers, starting with the MK14 in 1977. The loss of
9880-493: The hot plastic) and keeps the mould at a proper temperature to solidify the plastic at the most efficient rate. To ease maintenance and venting, cavities and cores are divided into pieces, called inserts , and sub-assemblies, also called inserts , blocks , or chase blocks . By substituting interchangeable inserts, one mould may make several variations of the same part. More complex parts are formed using more complex moulds. These may have sections called slides, that move into
10010-404: The injection and clamping cycles; however, aluminium moulds are cost-effective in low-volume applications, as mould fabrication costs and time are considerably reduced. Many steel moulds are designed to process well over a million parts during their lifetime and can cost hundreds of thousands of dollars to fabricate. When thermoplastics are moulded, typically pelletised raw material is fed through
10140-610: The introduction of the first "calculator on a chip", the MK6010 by Mostek , followed by Texas Instruments later in the year. Although these early hand-held calculators were very costly, these advances in electronics, together with developments in display technology (such as the vacuum fluorescent display , LED , and LCD ), led within a few years to the cheap pocket calculator available to all. In 1971, Pico Electronics and General Instrument also introduced their first collaboration in ICs,
10270-555: The logic circuits, appeared in the 1940s and 1950s. Electronic circuits developed for computers also had application to electronic calculators. The Casio Computer Company, in Japan , released the Model 14-A calculator in 1957, which was the world's first all-electric (relatively) compact calculator. It did not use electronic logic but was based on relay technology, and was built into a desk. The IBM 608 plugboard programmable calculator
10400-411: The material into a single connected network of molecules. As the chemical reaction occurs, the two fluid components permanently transform into a viscoelastic solid. Solidification in the injection barrel and screw can be problematic and have financial repercussions; therefore, minimising the thermoset curing within the barrel is vital. This typically means that the residence time and temperature of
10530-488: The material used and the size of the part. Larger parts require higher clamping force. Mould or die are the common terms used to describe the tool used to produce plastic parts in moulding. Since moulds have been expensive to manufacture, they were usually only used in mass production where thousands of parts were being produced. Typical moulds are constructed from hardened steel , pre-hardened steel, aluminium, and/or beryllium-copper alloy. The choice of material for
10660-548: The melting surfaces contacting the injected polymer. Dimensional differences can be attributed to non-uniform, pressure-induced deformation during injection, machining tolerances , and non-uniform thermal expansion and contraction of mould components, which experience rapid cycling during the injection, packing, cooling, and ejection phases of the process. Mould components are often designed with materials of various coefficients of thermal expansion. These factors cannot be simultaneously accounted for without astronomical increases in
10790-407: The method of building injection moulds. With technological developments, CNC machining became the predominant means of making more complex moulds with more accurate mould details in less time than traditional methods. The electrical discharge machining (EDM) or spark erosion process has become widely used in mould making. As well as allowing the formation of shapes that are difficult to machine,
10920-637: The mid-1960s. They included the Mathatronics Mathatron (1964) and the Olivetti Programma 101 (late 1965) which were solid-state, desktop, printing, floating point, algebraic entry, programmable, stored-program electronic calculators. Both could be programmed by the end user and print out their results. The Programma 101 saw much wider distribution and had the added feature of offline storage of programs via magnetic cards. Another early programmable desktop calculator (and maybe
11050-412: The mold is not only based on cost considerations, but also has a lot to do with the product life cycle . In general, steel moulds cost more to construct, but their longer lifespan offsets the higher initial cost over a higher number of parts made before wearing out. Pre-hardened steel moulds are less wear-resistant and are used for lower volume requirements or larger components; their typical steel hardness
11180-493: The mould causes the slides to move forward along the angle pins. A mould can produce several copies of the same parts in a single "shot". The number of "impressions" in the mould of that part is often incorrectly referred to as cavitation. A tool with one impression is often called a single impression (cavity) mould. A mould with two or more cavities of the same parts is usually called a multiple impression (cavity) mould. (Not to be confused with "Multi- shot moulding" {which
11310-399: The mould cavity through a gate and runner system. The mould remains cold so the plastic solidifies almost as soon as the mould is filled. The sequence of events during the injection mould of a plastic part is called the injection moulding cycle. The cycle begins when the mould closes, followed by the injection of the polymer into the mould cavity. Once the cavity is filled, a holding pressure
11440-404: The mould cools so that it can be ejected and be dimensionally stable. This cooling duration is dramatically reduced by the use of cooling lines circulating water or oil from an external temperature controller. Once the required temperature has been achieved, the mould opens and an array of pins, sleeves, strippers, etc. are driven forward to demould the article. Then, the mould closes and the process
11570-522: The mould through a sprue or gate in the injection mould; the sprue bushing is to seal tightly against the nozzle of the injection barrel of the moulding machine and to allow molten plastic to flow from the barrel into the mould, also known as the cavity. The sprue bushing directs the molten plastic to the cavity images through channels that are machined into the faces of the A and B plates. These channels allow plastic to run along them, so they are referred to as runners. The molten plastic flows through
11700-427: The number of cavities play a vital role in moulding costs, so does the complexity of the part's design. Complexity can be incorporated into many factors such as surface finishing, tolerance requirements, internal or external threads, fine detailing or the number of undercuts that may be incorporated. Further details, such as undercuts, or any feature that needs additional tooling, increases mould cost. Surface finish of
11830-711: The only other competitor in true commercial production, had sold 100 comptometers . It wasn't until 1902 that the familiar push-button user interface was developed, with the introduction of the Dalton Adding Machine, developed by James L. Dalton in the United States . In 1921, Edith Clarke invented the "Clarke calculator", a simple graph-based calculator for solving line equations involving hyperbolic functions. This allowed electrical engineers to simplify calculations for inductance and capacitance in power transmission lines . The Curta calculator
11960-426: The part from the mould. Insufficient draft can cause deformation or damage. The draft required for mould release is primarily dependent on the depth of the cavity; the deeper the cavity, the more draft necessary. Shrinkage must also be taken into account when determining the draft required. If the skin is too thin, then the moulded part tends to shrink onto the cores that form while cooling and cling to those cores, or
12090-408: The part may warp, twist, blister or crack when the cavity is pulled away. A mould is usually designed so that the moulded part reliably remains on the ejector (B) side of the mould when it opens, and draws the runner and the sprue out of the (A) side along with the parts. The part then falls freely when ejected from the (B) side. Tunnel gates, also known as submarine or mould gates, are located below
12220-415: The parting line or mould surface. An opening is machined into the surface of the mould on the parting line. The moulded part is cut (by the mould) from the runner system on ejection from the mould. Ejector pins, also known as knockout pins, are circular pins placed in either half of the mould (usually the ejector half), which push the finished moulded product, or runner system out of a mould. The ejection of
12350-426: The point where a basic calculator was affordable to most and they became common in schools. In addition to general purpose calculators, there are those designed for specific markets. For example, there are scientific calculators , which include trigonometric and statistical calculations. Some calculators even have the ability to do computer algebra . Graphing calculators can be used to graph functions defined on
12480-422: The power grid, was released at the start of the 1970s. The electronic calculators of the mid-1960s were large and heavy desktop machines due to their use of hundreds of transistors on several circuit boards with a large power consumption that required an AC power supply. There were great efforts to put the logic required for a calculator into fewer and fewer integrated circuits (chips) and calculator electronics
12610-486: The pressure should be sufficient to allow for the desired speed, pressure limitations during this stage are undesirable. Once the cavity is 98% full, the machine switches from velocity control to pressure control , where the cavity is "packed out" at a constant pressure, where sufficient velocity to reach desired pressures is required. This lets workers control part dimensions to within thousandths of an inch or better. Although most injection moulding processes are covered by
12740-420: The process allows pre-hardened moulds to be shaped so that no heat treatment is required. Changes to a hardened mould by conventional drilling and milling normally require annealing to soften the mould, followed by heat treatment to harden it again. EDM is a simple process in which a shaped electrode, usually made of copper or graphite, is very slowly lowered onto the mould surface over a period of many hours, which
12870-421: The process his leibniz wheel , but who couldn't design a fully operational machine. There were also five unsuccessful attempts to design a calculating clock in the 17th century. The 18th century saw the arrival of some notable improvements, first by Poleni with the first fully functional calculating clock and four-operation machine, but these machines were almost always one of a kind . Luigi Torchi invented
13000-631: The processor's speed, and is measured in clock cycles per second or hertz (Hz) . For basic calculators, the speed can vary from a few hundred hertz to the kilohertz range. A basic explanation as to how calculations are performed in a simple four-function calculator: To perform the calculation 25 + 9 , one presses keys in the following sequence on most calculators: 2 5 + 9 = . Other functions are usually performed using repeated additions or subtractions. Most pocket calculators do all their calculations in binary-coded decimal (BCD) rather than binary. BCD
13130-412: The raw material forward, mixes and homogenises the thermal and viscous distributions of the polymer, and reduces the required heating time by mechanically shearing the material and adding a significant amount of frictional heating to the polymer. The material feeds forward through a check valve and collects at the front of the screw into a volume known as a shot . A shot is the volume of material that
13260-409: The raw material manufacturers in paper bags. With injection moulding, pre-dried granular plastic is fed by a forced ram from a hopper into a heated barrel. As the granules are slowly moved forward by a screw-type plunger, the plastic is forced into a heated chamber, where it is melted. As the plunger advances, the melted plastic is forced through a nozzle that rests against the mould, allowing it to enter
13390-508: The real line, or higher-dimensional Euclidean space . As of 2016 , basic calculators cost little, but scientific and graphing models tend to cost more. Computer operating systems as far back as early Unix have included interactive calculator programs such as dc and hoc , and interactive BASIC could be used to do calculations on most 1970s and 1980s home computers. Calculator functions are included in most smartphones , tablets , and personal digital assistant (PDA) type devices. With
13520-409: The runner and enters one or more specialised gates and into the cavity geometry to form the desired part. The amount of resin required to fill the sprue, runner and cavities of a mould comprises a "shot". Trapped air in the mould can escape through air vents that are ground into the parting line of the mould, or around ejector pins and slides that are slightly smaller than the holes retaining them. If
13650-441: The same parts or can be unique and form multiple different geometries during a single cycle. Moulds are generally made from tool steels , but stainless steels and aluminium moulds are suitable for certain applications. Aluminium moulds are typically ill-suited for high volume production or parts with narrow dimensional tolerances, as they have inferior mechanical properties and are more prone to wear, damage, and deformation during
13780-603: The same time). The Victor 3900 was the first to use integrated circuits in place of individual transistors , but production problems delayed sales until 1966. There followed a series of electronic calculator models from these and other manufacturers, including Canon , Mathatronics , Olivetti , SCM (Smith-Corona-Marchant), Sony , Toshiba , and Wang . The early calculators used hundreds of germanium transistors , which were cheaper than silicon transistors , on multiple circuit boards. Display types used were CRT, cold-cathode Nixie tubes , and filament lamps . Memory technology
13910-505: The screen flashes and all keys except the clear key are rendered inoperable to inform the user of the error. An independent memory register could read information from the screen, and information could only be taken from the memory onto the screen. Five keys were used for memory operations. The Sovereign used a Mostek MK50321N main integrated circuit , the same as the Sinclair Wrist Calculator and some variants of
14040-433: The small button cell batteries and comparatively high power consumption meant a short battery life compared to the competition. Calculator An electronic calculator is typically a portable electronic device used to perform calculations , ranging from basic arithmetic to complex mathematics . The first solid-state electronic calculator was created in the early 1960s. Pocket-sized devices became available in
14170-803: The strength and function required for the final part, as well as the cost, but also each material has different parameters for moulding that must be taken into account. Other considerations when choosing an injection moulding material include flexural modulus of elasticity, or the degree to which a material can be bent without damage, as well as heat deflection and water absorption. Common polymers like epoxy and phenolic are examples of thermosetting plastics while nylon , polyethylene , and polystyrene are thermoplastic. Until comparatively recently, plastic springs were not possible, but advances in polymer properties make them now quite practical. Applications include buckles for anchoring and disconnecting outdoor-equipment webbing. Injection moulding machines consist of
14300-403: The time" astronomical device), development of computing tools arrived near the start of the 17th century: the geometric-military compass (by Galileo ), logarithms and Napier bones (by Napier ), and the slide rule (by Edmund Gunter ). The Renaissance saw the invention of the mechanical calculator by Wilhelm Schickard in 1623, and later by Blaise Pascal in 1642. A device that
14430-521: The time. The Sovereign was unusual because the casing was made from pressed steel , which gave it a much higher quality feel compared to injection moulded plastic. This allowed a variety of paint and plating options, including black painted, chrome-plated , silver-plated, and gold-plated, and a limited edition silver-plated version, inscribed to commemorate the Silver Jubilee of Queen Elizabeth II in 1977, were also produced. Asprey of London
14560-410: The total number of available materials for injection moulding has increased at a rate of 750 per year; there were approximately 18,000 materials available when that trend began. Available materials include alloys or blends of previously developed materials, so product designers can choose the material with the best set of properties from a vast selection. Major criteria for selection of a material are
14690-738: The track number in BCD, limiting them to 99 tracks.) The same argument applies when hardware of this type uses an embedded microcontroller or other small processor. Often, smaller code results when representing numbers internally in BCD format, since a conversion from or to binary representation can be expensive on such limited processors. For these applications, some small processors feature BCD arithmetic modes, which assist when writing routines that manipulate BCD quantities. Where calculators have added functions (such as square root, or trigonometric functions ), software algorithms are required to produce high precision results. Sometimes significant design effort
14820-415: The trapped air is not allowed to escape, it is compressed by the pressure of the incoming material and squeezed into the corners of the cavity, where it prevents filling and can also cause other defects. The air can even become so compressed that it ignites and burns the surrounding plastic material. To allow for removal of the moulded part from the mould, the mould features must not overhang one another in
14950-458: The vast majority of all injection machines. The plastic injection moulding industry has evolved over the years from producing combs and buttons to producing a vast array of products for many industries including automotive, medical, aerospace, consumer products, toys, plumbing , packaging, and construction. Most polymers, sometimes referred to as resins, may be used, including all thermoplastics, some thermosets, and some elastomers. Since 1995,
15080-643: The very wide availability of smartphones and the like, dedicated hardware calculators, while still widely used, are less common than they once were. In 1986, calculators still represented an estimated 41% of the world's general-purpose hardware capacity to compute information. By 2007, this had diminished to less than 0.05%. Electronic calculators contain a keyboard with buttons for digits and arithmetical operations; some even contain "00" and "000" buttons to make larger or smaller numbers easier to enter. Most basic calculators assign only one digit or operation on each button; however, in more specific calculators,
15210-420: The volume used of the former being considerably higher. Thermoplastics are prevalent due to characteristics that make them highly suitable for injection moulding, such as ease of recycling, versatility for a wide variety of applications, and ability to soften and flow on heating. Thermoplastics also have an element of safety over thermosets; if a thermosetting polymer is not ejected from the injection barrel in
15340-624: Was IBM's first all-transistor product, released in 1957; this was a console type system, with input and output on punched cards, and replaced the earlier, larger, vacuum-tube IBM 603 . In October 1961, the world's first all-electronic desktop calculator, the British Bell Punch /Sumlock Comptometer ANITA ( A N ew I nspiration T o A rithmetic/ A ccounting) was announced. This machine used vacuum tubes , cold-cathode tubes and Dekatrons in its circuits, with 12 cold-cathode "Nixie" tubes for its display. Two models were displayed,
15470-578: Was a manufacturer of mechanical calculators that had decided that the future lay in electronics. In 1964 more all-transistor electronic calculators were introduced: Sharp introduced the CS-10A , which weighed 25 kilograms (55 lb) and cost 500,000 yen ($ 4555.81), and Industria Macchine Elettroniche of Italy introduced the IME 84, to which several extra keyboard and display units could be connected so that several people could make use of it (but apparently not at
15600-589: Was a paper tape. As a result of the "Cal-Tech" project, Texas Instruments was granted master patents on portable calculators. The first commercially produced portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the Sanyo ICC-0081 "Mini Calculator", the Canon Pocketronic, and the Sharp QT-8B "micro Compet". The Canon Pocketronic was
15730-553: Was also the first calculator to use an LED display, the first hand-held calculator to use a single integrated circuit (then proclaimed as a "calculator on a chip"), the Mostek MK6010, and the first electronic calculator to run off replaceable batteries. Using four AA-size cells the LE-120A measures 4.9 by 2.8 by 0.9 inches (124 mm × 71 mm × 23 mm). The first European-made pocket-sized calculator, DB 800
15860-419: Was an implied unconditional branch (GOTO) at the end of the operation stack, returning the program to its starting instruction. Thus, it was not possible to include any conditional branch (IF-THEN-ELSE) logic. During this era, the absence of the conditional branch was sometimes used to distinguish a programmable calculator from a computer. The first Soviet programmable desktop calculator ISKRA 123 , powered by
15990-436: Was at times somewhat over-promoted as being able to perform all four arithmetic operations with minimal human intervention. Pascal's calculator could add and subtract two numbers directly and thus, if the tedium could be borne, multiply and divide by repetition. Schickard's machine, constructed several decades earlier, used a clever set of mechanised multiplication tables to ease the process of multiplication and division with
16120-474: Was developed in 1948 and, although costly, became popular for its portability. This purely mechanical hand-held device could do addition, subtraction, multiplication and division. By the early 1970s electronic pocket calculators ended manufacture of mechanical calculators, although the Curta remains a popular collectable item. The first mainframe computers, initially using vacuum tubes and later transistors in
16250-505: Was followed the next year by the SR-50 which added log and trig functions to compete with the HP-35, and in 1977 the mass-marketed TI-30 line which is still produced. Injection molding Injection moulding (U.S. spelling: injection molding ) is a manufacturing process for producing parts by injecting molten material into a mould, or mold . Injection moulding can be performed with
16380-592: Was made in May 1971 by Digitron in Buje , Croatia (former Yugoslavia ) with four functions and an eight-digit display and special characters for a negative number and a warning that the calculation has too many digits to display. The first American-made pocket-sized calculator, the Bowmar 901B (popularly termed The Bowmar Brain ), measuring 5.2 by 3.0 by 1.5 inches (132 mm × 76 mm × 38 mm), came out in
16510-608: Was one of the leading edges of semiconductor development. U.S. semiconductor manufacturers led the world in large scale integration (LSI) semiconductor development, squeezing more and more functions into individual integrated circuits. This led to alliances between Japanese calculator manufacturers and U.S. semiconductor companies: Canon Inc. with Texas Instruments , Hayakawa Electric (later renamed Sharp Corporation ) with North-American Rockwell Microelectronics (later renamed Rockwell International ), Busicom with Mostek and Intel , and General Instrument with Sanyo . By 1970,
16640-466: Was relatively simple compared to machines in use today: it worked like a large hypodermic needle , using a plunger to inject plastic through a heated cylinder into a mould. The industry progressed slowly over the years, producing products such as collar stays , buttons, and hair combs(generally though, plastics, in its modern definition, are a more recent development c. 1950s ). The German chemists Arthur Eichengrün and Theodore Becker invented
16770-590: Was rumoured to have produced two Sovereigns in solid gold, costing £2,750 each. The design, by John Pemberton, won the Design Council Award in 1977, as the Executive had in 1973, and there are examples in the collection of the Museum of Modern Art in New York . Sovereigns are highly collectible, and used models command high prices. As well as addition, subtraction, multiplication and division, it had reciprocal and square-root functions , and
16900-767: Was usually based on the delay-line memory or the magnetic-core memory , though the Toshiba "Toscal" BC-1411 appears to have used an early form of dynamic RAM built from discrete components. Already there was a desire for smaller and less power-hungry machines. Bulgaria's ELKA 6521 , introduced in 1965, was developed by the Central Institute for Calculation Technologies and built at the Elektronika factory in Sofia . The name derives from EL ektronen KA lkulator , and it weighed around 8 kg (18 lb). It
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