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.