Rapid prototyping technology and development

Rapid Prototyping (RP) technology, also known as rapid prototyping technology, is one of the rapidly developing manufacturing technologies in the world today. Rapid prototyping technology is a computer-controlled, based on the principle of discrete, stacked with different methods of accumulation of materials, and ultimately complete the parts of the forming and manufacturing technology.

1, from the forming point of view, the parts can be regarded as "point" or "surface" superposition. The geometrical information of "point" or "face" is discretized from the CAD electronic model, and then combined with the information of the forming process parameters, the material is regulated to accumulate the parts from point to surface and from surface to surface.

2, from the manufacturing point of view, it is based on CAD modeling to generate parts of the three-dimensional geometric information, control multi-dimensional system, by laser beam or other methods of material layer by layer to form a prototype or parts.

The main features of RP technology are:

1, rapid RP manufacturing technology is the concurrent engineering of complex prototyping or parts manufacturing an effective means to enable product design and mold production simultaneously, thereby enhancing R & D efficiency, shorten the product design cycle, greatly reducing the cost of new product development And risk, for the smaller size, shaped products are particularly applicable.

2, CAD / CAM technology integration Design and manufacture of integration has been a difficult point, computer-aided process (CAPP) at this stage because it can not and CAD, CAM completely seamless docking, which is restricting the manufacturing information And rapid prototyping technology integrated CAD, CAM, laser technology, numerical control technology, chemical engineering, material engineering and many other technologies, making the concept of design and manufacturing integration to achieve a perfect one.

3, complete reproduction of three-dimensional data through rapid prototyping and manufacturing of complete parts, complete true reproduction of three-dimensional modeling, regardless of the outer surface of the contour or the cavity of the shaped hole, can be true and accurate completion of modeling, basically no longer need to help External devices to repair.

4, a wide range of molding materials So far, all kinds of RP equipment used in a variety of materials, resin, nylon, plastic, paraffin, paper and metal or ceramic powder, basically meet the vast majority of products on the material Mechanical performance requirements.

5, to create significant economic benefits Compared with the traditional mechanical processing, development costs to save more than 10 times, the same rapid prototyping technology to shorten the enterprise product development cycle, so that in the new product development process of repeated revisions to the design of the program greatly Reduce, and basically eliminate the problem of modifying the mold, to create economic benefits is obvious.

6, the application of industry-wide RP technology After years of development, technically has basically formed a system, the same can be applied to the industry has gradually expanded, from product design to mold design and manufacturing, materials engineering, medical research, Culture and art, construction, etc. are gradually using the RP technology, making RP technology has broad prospects.

Direction of development

From the current RP technology research and application status, rapid prototyping technology for further research and development work mainly in the following areas:

(1) the development of good performance rapid prototyping materials, such as low cost, easy to shape, small deformation, high strength, durable and pollution-free forming material.

(2) to improve the processing speed RP system and open up the manufacturing process of parallel methods.

(3) to improve the reliability of the rapid prototyping system to improve its productivity and the ability to produce large pieces of equipment to optimize the structure, especially to improve the accuracy of forming parts, surface quality, mechanical and physical properties, for further mold processing and functional experiments provide the basis .

 (4) the development of rapid prototyping of high-performance RPM software. Improve the speed and accuracy of data processing, research and development using CAD raw data direct slicing method to reduce the STL format conversion and slicing process generated by the loss of accuracy.

(5) the development of new forming energy.

6) rapid prototyping method and process improvement and innovation. Direct metal forming technology will become the future research and application of another hot spot.

(7) rapid prototyping technology and CAD, CAE, RT, CAPP, CAM and high precision automatic measurement, reverse engineering integration research.

(8) to improve network services research efforts to achieve remote control.

Blister Mold and material selection

1, the choice of blister c mold

Blister mold generally have plaster mold, copper mold and aluminum mold

Gypsum mold: plaster molding in the semi-wet state, and then drying mold, plaster mold low cost, easy to modify, but the plaster mold precision is not high enough, the surface is not smooth and fragile is not durable, so it is often used to fight To do the electroplating of copper mold or some of the requirements of small-batch production of plastic mold.

Aluminum mold: with aluminum ingots through the machinery (lathes, milling machines, CNC, etc.) from processing.

Aluminum mold high precision, smooth surface and durable, but the price is very expensive, aluminum mold is generally used in high precision copper mold not reach the blister products.

Electroplated copper mold: Plaster mold made of samples, the plating layer of copper shell is the electroplating copper mold, the cost of relatively high plaster mold, but much cheaper than aluminum mold, because of its smooth and durable surface, low cost, electroplating Copper mold is the most commonly used a plastic mold.

2， the choice of plastic material

Blister packaging products include: bubble shells, trays, plastic boxes, as well as: vacuum cover, blister, and so on.

Blister products are only plastic sheet material, film thickness is generally not more than 1.5MM, commonly used sheet: PVC, PET, PP, PS and on this basis, flocking sheet, gold-plated sheet and anti-static sheet .

PVC: the most commonly used plastic material, soft, toughness, good plasticity, can be made transparent and a variety of colors, commonly used transparent PVC packaging electronics, cosmetics, toys, gifts and other products.

PET (A-PET): hard, good toughness, high strength, bright surface, environmentally friendly non-toxic, transparent and a variety of colors of the sheet. Disadvantages of PET high-frequency heat more difficult, the price is much more expensive than PVC, this material is often required to replace high-end and environmentally friendly products, PVC

PS: small density (light), environmental non-toxic, plasticity is very good, toughness is not easy to brittle, can not be made of transparent material, it can only be made at the end of care plastic, because of its easy to crack,

PP: material is particularly soft, tough, environmentally friendly non-toxic, high temperature, often made of food containers or other high temperature packaging products; but its poor plasticity, processing difficulties, poor surface gloss, and the processing of color change shallow.

PET-G: physical properties with the A-PET almost, but high-frequency heat, the price is more expensive than A-PET 80%

3, The determinants of price of plastic products

Blister = unit material cost of materials + energy + labor + transport + profits

Energy consumption: Blister is through the thermal processing, power consumption relative to other industries larger, roughly for the material cost of 8%

Artificial: Blister mainly by machine production, less artificial, roughly 10% of the cost of materials,

Transportation: According to the customer from the factory and distance,

Profit: Plastic factory net profit is generally low, 12% -20%, depending on the payment period, 30 days checkout is 14%

Material cost: The material cost of the product is relatively complicated. Before the calculation, the following data should be clarified:

Raw material price: according to the use of the product, to determine what kind of material and grade of material, to find the lowest price of this material suppliers

Film Thickness: Extending The product must be made of thick film, according to the shape of the thickness and shape of the various parts of the

The number of typesetting: according to the size and shape of the product, the number of molds can be calculated in a version, the density will reduce the quality of products, thinning will increase the material loss, so that the cost of material loss rate: the main factor is the product shape, The number and size of the chassis fit with the degree of plastic, the shape of the more Founder, the greater the output, the smaller the loss rate

Material Selection of Die Casting

The service life of Die-casting mold and die-casting mold material is closely related. Die-casting mold zero, the components are mainly divided into contact with the metal parts, sliding parts and mold parts with structural parts. Die-casting mold cavity and runner and other components in the metal pressure casting production process, directly with the high temperature, high pressure, high-speed metal liquid contact. On the one hand by the metal liquid direct erosion, wear, high temperature oxidation and corrosion. On the other hand, due to the high efficiency of the production, the mold temperature rise and decrease is very severe, and the formation of periodic changes. Therefore, the die casting mold working environment is very bad. Therefore, attention should be paid to the selection of the material for manufacturing the die casting mold.

① a good malleability and machinability.

② high temperature red high hardness, high temperature strength, anti-tempering stability and impact toughness.

 ③ has good thermal conductivity and fatigue resistance.

④ have enough high temperature oxidation resistance.

 ⑤ small thermal expansion coefficient.

⑥ high wear resistance and corrosion resistance.

 ⑦ has good hardenability and a smaller heat treatment deformation rate.

Selection of die-casting materials, should be based on product performance, process performance, production conditions, economy and the characteristics of die-casting materials and other factors, a reasonable choice of the right die-casting material. Commonly used mechanical parts die-casting materials include aluminum alloy, zinc alloy and magnesium alloy.

    Aluminum alloy is currently the most widely used die-casting materials, widely used in the automotive industry, motorcycle industry, aerospace and so on. Aluminum features are as follows:

    1) aluminum alloy density is small, only iron, copper, zinc 1/3 or so, than the strength and specific stiffness is its outstanding advantages.

    2) aluminum alloy has a good electrical conductivity, thermal conductivity.

    3) aluminum alloy oxidation resistance and corrosion resistance. In the air, the surface of aluminum is easy to generate a layer of dense oxidation of sulfur dioxide film, can prevent further oxidation.

    4) aluminum alloy has good die-casting performance. Aluminum alloy die-casting process is simple, forming and cutting process performance is good, with high mechanical properties and corrosion resistance, is the most promising alternative to steel casting alloy.

    5) the high temperature mechanical properties of aluminum alloy is very good, in the low temperature work also maintain good mechanical properties.

    6) The shortcomings of aluminum alloy is easy to produce a large concentration of shrinkage at the final solidification. In addition, the aluminum alloy and iron have a strong affinity, easy to stick mold, cold chamber die casting machine in the pressure.

     Zinc alloy is also more common, zinc alloy features are as follows:

    1) zinc alloy has excellent casting performance, mechanical properties, toughness, in the traditional mechanical parts, hardware, locks, toys and other industries is widely used.

    2) zinc alloy has excellent electrical and thermal conductivity, good vibration damping characteristics, good electromagnetic shielding performance in the electronics, telecommunications, home appliances on the application of growing.

    3) zinc alloy is a universal, reliable, low-cost materials, easy to die-casting production. Zinc alloy has good die-casting performance, making it easier to die-casting complex shape, thin-walled, high dimensional accuracy of the product. Due to the thin-walled casting properties of the zinc alloy, it is possible to achieve a reduction in the weight and cost of the product.

    4) Compared with aluminum alloy and magnesium alloy, zinc alloy has a high tensile strength, yield strength, impact toughness and hardness, good elongation.

    5) Zinc alloy die casting surface is very smooth, can not be used directly for surface treatment, but also relatively easy to carry out a variety of surface treatment, such as polishing, plating, spraying, in order to obtain better surface quality.

    6) low melting point of zinc alloy, melting at 385 ℃, compared to aluminum and magnesium alloy, zinc alloy is most likely to die casting.

    7) poor corrosion resistance. When zinc, lead, cadmium and tin in impurity elements exceed the standard, they will gradually aging and deformation, showing the volume expansion, mechanical properties (especially plastic) decreased significantly, a long time will rupture.

    8) timeliness. The use of time is too long, zinc alloy die casting the shape and size will be slightly changed.

9) Zinc alloy should not be used in high temperature and low temperature working environment. Zinc alloy has good mechanical properties at room temperature, but the tensile strength at low temperature and low temperature impact properties are significantly decreased.

    There is also a magnesium alloy, magnesium alloy features are as follows:

    1) magnesium alloy known as the "2 1 century green engineering materials", the density of aluminum alloy 2/3, steel 1/4, but the specific strength and specific stiffness are better than aluminum and steel, far higher In engineering plastics, is an excellent, lightweight structural materials.

    2) Magnesium alloy has a good energy absorption and vibration absorption characteristics, for the product shell can reduce the noise transmission, vibration absorption for the movement of parts and components to extend the service life of parts.

    3) has a good electromagnetic shielding, can provide electronic products, anti-electromagnetic radiation.

    4) good rigidity, impact resistance.

    5) ductility is good, easy to shape, can make the product design with flexibility, improve product quality.

    6) low melting point of magnesium alloy, making low-temperature deformation, high dimensional accuracy, is conducive to a mold forming; and iron affinity, adhesion to the mold is small, The flow properties facilitate the production of complex pieces and small pieces.

    7) The best machining performance, the required cutting force is small, cutting effect is good, long tool life.

    8) heat, and second only to aluminum.

    9) Dimensional stability, environmental temperature and time changes on the size of small.

    10) can be 100% regeneration.

    11) magnesium alloy in the air easily oxidized, magnesium alloy die casting after forming must be surface treatment, improve corrosion resistance, improve the surface quality of parts. Commonly used surface treatment methods include electroplating, spraying, anodizing and so on. Magnesium alloy has the same high-temperature brittleness, hot cracking tendency of the shortcomings.

Injection mold and die-casting characteristics

Injection mold features:

1) The design is difficult because the plastic melt belongs to the viscoelastic body, the melt flow process with shear stress, shear rate changes, the flow of macromolecules in the direction of flow direction. After the cavity is full of melt is partially compressed, and in the cooling and curing process of plastic? Very complex, all parts of the cavity, the shrinkage of the direction are different, and different types of grades of resin to close? Rates are also very different. All of the above, are given to the design of injection mold has brought a lot of difficulty. This difficulty is not the other mechanical products.

 2) the high cost of manufacturing molds are specific to the shape of plastic products, specifications design, so a variety of mold structure very different, it is not possible to buy in the market, can not be mass production. It is only possible in a special factory for single-piece production, and mold life is longer, the possibility of repeated manufacturing mold is very small, so the mold manufacturing costs are higher.

 3) short production cycle The current product is extremely competitive, who products can be put on the market, it is possible to grab the first business opportunities, therefore, each manufacturer in race against time, as soon as possible on the market and make every effort, which requires Injection from the design, manufacture, production should try to shorten the time required to shorten the production cycle as far as possible in order to grab the market, grab the benefits.

 4) high technological content of injection molding products, some of the shape is very complex, the size, precision requirements are high, and mostly the main components, which to the design and manufacture of injection mold has brought great difficulty, in order to be able to press Quality mold manufacturing time, must be invested elite, must focus on advanced machinery manufacturing technology.

Compared with other metal forming processes, the characteristics of Die casting are:

(1) the productivity is extremely high, the production process is easy to realize the mechanization and the automation. General cold chamber die casting machine every eight hours can be 600 to 700 times the die-casting, hot-pressing die-casting machine every eight hours to die-casting 3 000 to 7 000 times. And a die-casting mold cavity often more than one, so that the number of die-casting production will also exponentially increased.

(2) high dimensional accuracy of the casting, the size of stability, consistency, and less processing allowance and a good assembly. Die-casting of the accuracy of up to IT11 ~ IT13 level, and sometimes up to IT9 level. Surface roughness values ​​are generally Ra0.8 ~ 3.2, the lowest up to Ra0.4. General die castings only a few parts of the size of machining, and some parts without even mechanical processing can be directly assembled to use. This high utilization of materials, up to 60% to 80%, rough utilization rate of 90%.

(3) casting dense organization, with high strength and hardness. As the metal liquid is solidified under pressure, and because of high-speed filling, the cooling rate is extremely fast, so that the casting surface to generate a layer of cold hard layer (about 0.3 ~ 0.8mm), the layer of metal grain is small, dense organization. Therefore, high strength and hardness of die-casting, solid wear-resistant. When the die wall thickness is appropriate and uniform, its strength is higher.

(4) can be complex casting shape, clear-cut thin-walled deep cavity casting, because the liquid metal under high pressure to maintain high mobility. The minimum wall thickness of zinc alloy die-casting parts can reach 0.3 mm, aluminum alloy is about 0.5 mm. The minimum casting diameter is 0.7 mm and the minimum pitch of the castable thread is 0.75 mm.

(5) Inlay casting method eliminates the assembly process, simplify the manufacturing process. Parts of other materials such as magnets, brass sleeves and insulating materials can be embedded directly into specific parts of the die casting to meet specific requirements, eliminating the need for assembly processes and simplifying the manufacturing process.

(6) casting the existence of porosity, but generally still meet the requirements. As the filling of liquid metal is extremely fast, it is difficult to completely remove the gas entrained in the cavity during filling, which results in the presence of pores and oxidized inclusions in the die castings, thereby reducing the quality of the die castings. Therefore, the general die casting can not be heat treatment, and should not work at high temperatures. Similarly, do not want to mechanical processing, so as not to expose the pores under the casting surface.

(7) die-casting machine pressure chamber and die casting mold cavity material limits the type of die-casting alloys. High melting point ferrous metal die casting die because of its short life and difficult to die in the actual production. In the same alloy, there are grades restrictions, it is because of the characteristics of the die-casting process, such as chilling, shrinkage stress, filling conditions, such as molding.

(8) The size of die-casting die-casting machine by clamping force and size constraints mold, so the production of large-scale die casting production is limited. At present, large-scale die-casting machine has been developed, large parts die casting problem is gradually being resolved.

(9) die-casting process is only suitable for mass production. As the high price of die-casting machine, die casting mold manufacturing costs are high, long hours, maintenance costs are high, so the total cost of production, not small batch production.

Plastic applications and advantages in the medical industry

Plastic application in the medical industry：

Medical equipment related to the pharmaceutical industries, machinery, electronics, plastics, etc., wherein the plastic rapid development of medical devices. Since the 1930s people first used synthetic polymer materials - since celluloid film is formed as an artificial kidney dialysis membrane used in clinical success, polymer materials are gradually replacing traditional inorganic materials such as metal, glass, ceramic, apatite stone for the preparation of medical devices.

This is reason:

(1)     polymer material having good mechanical properties and chemical stability, more suitable for medical use;

(2) polymer material rich source of inexpensive, disposable medical supplies made for avoiding the problem of sterilization and secondary infection due to the high cost of traditional materials and products have caused repeated use;

(3) having a plastic or modified more easily get a good histocompatibility and blood compatibility of products;

(4) Plastic low production costs, for a variety of molding methods, ease of processing into complex shapes and the development of new medical products.

Plastics in the medical industryadvantages:

From medicines and pharmaceutical packaging, the needle tube, hose, disposable surgical instruments and other medical equipment can be seen in the presence of plastic instruments.

Disposable medical device market demand potential is why so big, its main advantage is the following aspects:

1, light weight, effort, will help reduce fatigue caused by surgery doctors for a long time.

2, toughness is good, strong anti-permeability, durability, some plastics can also be used normally at high temperatures.

3, transparent, medical procedures can be better observed, especially during surgery.

4, easy to shape, for the production of a variety of shapes, complex medical equipment and supplies, and simply use the low-cost production process. High-temperature sterilization using disinfectant or corrosion does not occur or the color change phenomenon.

5, compared to metals and other raw materials, low cost, more suitable for the production of disposable consumables, after sterilization as packaging materials help to reduce the risk of infection.

6, compared with ceramic or glass and other fragile materials, the use of more safety, especially as packaging materials.

With the increase of the proportion of population growth and an aging population, the demand for plastic medical equipment continued to expand, particularly into the human body equipment. The use of medical equipment from a single to diversified development, the volume size is shrinking, now an equipment can replace conventional multiple pieces of equipment. Because many outstanding advantages of plastic medical equipment, pharmaceutical industry in the future course of development, its market share and influence will grow.

The hot runner role in injection molding

80 %of life goods need to through the injection molding

Mold is closely related to our life, More than 90% of the life of the article to be processed through the die is made,While 80% of goods go through the plastic molding, plastic mold temperature should reach 300 ℃ or more. Due to the special shape of the plastic mold, with traditional insulation materials can not be insulated on the lower mold high temperature heat loss of a great, severe heat loss, high temperature metal mold thermal fatigue loss is large, and so on. Plastic mold heat great loss, not only directly increase the cost of production, but also due to frequent replacement of the mold caused by mass production line shut down frequently result in greater economic losses.

Hot runner injection molding is used in conjunction with the mold, and play a very important role, such as in the production of ultra-thin plastic injection parts, by using the runner can easily produce high-precision, high-quality products out; for illiquid injection molding material by using a runner can improve the flow of raw materials, to ensure smooth production of injection molding; for some large plastic parts such as car bumpers and door panels, rear shell TV, air conditioning and so on through the hot runner can shell very difficult injection molding becomes relatively simple.

Ues hot runner to reduce injection molding products cost

In the multi-cavity injection mold, the lack of hot runner molding is difficult, it can be said so far is to ensure the hot runner runner balance of the best technology. Because of the presence of plastic hang shear forces in the flow, regardless of the geometry of a mold having more than a reasonable balance, the weight of the molded product is difficult to come out of the same, especially in terms of multi-cavity molds.

For plastics processors, as long as there is a certain volume of injection molding using a hot runner it is quite economical, because the hot runner nozzle to help businesses get rid of in the production of injection molding, which not only saves raw materials, and to cut labor costs and make products more perfect appearance. We all know that in most cases the drain can not be reused, if not at times the weight of the hot runner nozzle and the weight of the product is almost, if the traditional way means that the injection nozzle producing a product must be a product of almost a waste of raw materials as waste, and therefore only this not only saves raw materials, and to cut labor costs, but also make the product more perfect and beautiful. In addition, the runner also help reduce mold wear, extend die life. In general, the hot runner mold life is twice as small inlet of the mold.

Our company offers a reasonable solution

Runner simple composition, but each component plays an important role. Generally good quality hot runner design and structure of the material requirements are very high. We can according to the customer's product, the design a reasonable solution, to ensure the hot runner injection molding system can play a maximum efficiency. As our company uses Han Guorui runner, the choice of heaters and temperature line all imported from South Korea, the steel used for all materials imported from Japan, which is to ensure the quality of these hot runner prerequisite.

Rapid Prototyping Manufacturing

Rapid Prototyping (Rapid PrototypingManufacturing, abbreviated RPM), high-tech manufacturing technology is based on a material deposition method, it is considered the last 20 years, a major achievement in the field of manufacturing. It combines mechanical engineering, CAD, reverse engineering, layered manufacturing technology, numerical control technology, materials science, laser technology in one automatically, directly, quickly and accurately convert design to prototype with a certain function or direct manufacturing of parts , so as part prototyping, calibration, etc. the new design provides a cost-effective means of achieving. That is, rapid prototyping technology is the use of three-dimensional CAD data, through rapid prototyping machine, the stacked layers of material into a physical prototype.

Rapid Prototyping Features

(1) prototyping materials used are not limited to, a variety of metallic and non-metallic materials can be used;

(2) prototype reproducibility, high interchangeability;

(3) regardless of the manufacturing process prototyping geometry, more favorable when machining complex surfaces;

(4) Processing cycle is short, low-cost, independent of the degree of cost and complexity of products, general manufacturing costs by 50%, saving more than 70% of the processing cycle;

(5) a high degree of technology integration, to achieve the integration of design and manufacturing;

The practical application of rapid prototyping technology, mainly in the following aspects:

(1) Application of the new product design process of rapid prototyping technology to build a new product development model for industrial product design and development staff. The use of RP technology to quickly, directly and accurately design ideas into physical model has a certain function (sample), which not only shorten the development cycle and reduce development costs, but also enable enterprises occupy the first in the fierce competition in the market machine.

(2) in the field of machinery manufacturing technology due to RP own characteristics, so that it is in the manufacture of machinery for a wide range of applications, used for manufacturing a single-piece, small batch manufacturing metal parts. Some special complex parts, because only single-piece production, or less than 50 small quantities, usually can be molded directly by RP technology, low cost, short cycle.

(3) rapid tooling traditional mold for a long time and high cost. The rapid prototyping technology with traditional mold manufacturing technology, can greatly shorten the development cycle of the mold manufacturing, increased productivity, it is an effective way to mold design and manufacturing weaknesses addressed. Rapid Prototyping technology in mold manufacturing can be divided into direct and indirect molding molding two types of direct molding is the use of RP technology directly stacked to create a mold, indirect molding is a rapid prototyping system first part, and then copy the parts obtain the desired mold.

Rapid Prototyping Development Direction

From the current status of research and application of RP technology point of view, further research and development of rapid prototyping technology, mainly in the following aspects:

（1）Rapid development of good performance molding material, such as low cost, easy to shape, small deformation, high strength, durability and non-polluting molding material.

(2) increase the processing speed RP system and open up a parallel process for manufacture.

(3) rapid prototyping systems to improve reliability, increase their productivity and production of large capacity, optimize the device structure, in particular to improve the forming precision, surface quality, mechanical and physical properties of the member, provide a basis for further mold and functional assays .

（4）RPM high-performance software the development of rapid prototyping. Improve the speed and accuracy of data processing, research and development of the use of the original CAD data directly slice of ways to reduce the STL format conversion generated by the slicing process and loss of accuracy.