Export injection mold design standards and processes

Time:2019-03-13 15:01:58 / Popularity: / Source:

  • Introduction
What we usually call export molds are generally divided into three categories: one is to export molds in Europe; the second is to export molds in Japan and South Korea; the third is to export molds in North America. Main basis for such classification is to classify according to existing international mold standard system.
  • Standard system
At present, in plastic moulding industry, there are three major categories of mold standards in the world: Japanese mold standard system, North American mold standard system, and European mold standard system.
Japan's mold standard system, JIS STANDARD, the most commonly used standards are MISUMI plastic moulded parts standard, PUNCH plastic moulded parts standard, Ikegami gold mold parts standard, Fudeba mold standard, and Jialilai standard parts, Dongfa purple spring and other supporting standard parts.
North American mold standard system mainly refers to mold standards applied in North American countries such as United States, Colombia and Canada, and mold classification standard (SPI AN-102-78) developed by Society of Plastics Industry, which divides plastic molding into 5 Levels.
Plastic molding exported to United States are high-end commodity molds. The most famous mold standard parts suppliers are DME, PCS and Progressive. These three standard parts systems are widely used in North America countries such as United States, Canada and Colombia. Specific selection needs to be specified by customer.
European mold standard system mainly refers to plastic molding standard system of major industrial developed countries such as Germany, Britain, France, Italy, Netherlands and Spain. The most commonly used European injection moulding are German HASCO standard, German STRACK standard, and German EOC standard, British DMS standard, US DME European standard (metric standard), French ROUBARDIN standard and Austrian MEUSBURGER standard, the most famous of which is German HASCO standard.
    1. Mold grade
American Society of Plastics Industry (SPI AN-102-78) divides molds into five categories. Each of these five types of molds have different requirements, and this type of mold is only suitable for molds with injection moulding machines of 400 tons or less. This standard is based on the life of  mold, and mold is graded and widely used in export plastic moulding industry. This standard for mold classification is gradually becoming an international standard.
    A 101 type
Mold life of up to 1 million times or above, is a long-term production of precision molding. Requirements are as follows:
(1) Detailed molding design drawings are required.
(2) Hardness of mold blank material is at least 280BN (HRC 30, DME#2 steel / 4140 steel).
(3) Front and rear mold cores must at least reach hardness range of HRC48-50. Hardened tool steel should be used for all other accessories such as sliders, sloping roofs, press blocks and so on.
(4) Ejector mechanism should have a middle support orientation.
(5) Inclined surface and bottom surface of slider must be equipped with wear plates.
(6) Temperature control system shall be installed in front mold, rear mold, slider or other places on mould where it is needed.
(7) In life of mold, due to erosion of cooling water pipeline, quality of product is degraded and injection cycle is increased. It is recommended to have an insert or template for cooling water to be galvanized.
(8) All molds of this type are equipped with a zero degree side lock.
    B 102 type
Mold life can reach 500,000 to 1 million times, which is a mass production mold. Requirements are as follows:
(1) Detailed molding design drawings are required.
(2) Hardness of mold blank material is at least 280BN (HRC 30, DME#2 steel / 4140 steel).
(3) Front and rear mold cores must at least reach hardness range of HRC48-50. All other functional accessories should be heat treated.
(4) Temperature control system shall be installed in front mold, rear mold, slider or other places on mould where it is needed.
(5) All molds of this type must be equipped with a zero degree side lock.
(6) Following items may or may not be required, depending on final production quantity considerations. It is recommended to confirm whether there are following items when making a quote.
• Ejector guide
• Slider wear plate
• Plating water hole
• Plating cavity
    C 103 type
Mold life can reach 500,000 times. For products with medium-volume, required standards are as follows:
(1) Detailed molding design drawings are required.
(2) Hardness of die must be at least BHN165 (HRC17, DME#1 steel/1040 steel).
(3) Inner mold steel is P20 (28~32HRC) or high hardness (36~38HRC).
(4) Remaining requirements are subject to availability.
    D 104 type
Mold life can reach 100,000 times for low-volume production. Requirements are as follows:
(1) A mold structure drawing is required.
(2) Mold blank material P20 (28~32HRC) can be made of mild steel (1040 steel) or aluminum.
(3) Inner module can be made of aluminum, mild steel or other approved metal.
(4) Remaining requirements are subject to availability.
    E 105 type
Mold life is no more than 500 times. Used to produce a limited number of first boards or test dies, price is very cheap. Requirements are as follows:
Aluminum, cast iron or epoxy or any material can be used to produce a minimum number of tests as long as there is sufficient strength.
    2. Appearance standards
There is no uniform international standard for surface treatment of plastic molding cavities. There is no relevant standard in China. Selection criteria for mold etch in United States is MoldTech standard, which is widely used in various countries in North America. MoldTech has a factory in Dongguan, China, which is dedicated to serving Chinese customers. It can be used as a reference in molding design. Selection criteria for etch marks in Japanese customers is Nihong standard.
  • Mold steel
    1. North American mold steel
The most commonly used steel for front and rear mold cores is H13 and S7. H series steel is a high temperature mold steel with good hardness, wear resistance and ability to withstand high pressure and intermittent impact. Heat treatment hardness of H13 is HRC48-52. S series steel is anti-impact die steel, there are 7 steel grades, namely S1-S7, carbon content is 0.4%-0.6%, the most commonly used steel in plastic mold is S7, its chemical composition is C0.45-0.55; Mn 0.20- 0.90; P≤0.030; S≤0.030; Si0.20-1.00; Cr3.00-3.50; V ≤0.35; Mo-1.30, because it belongs to chrome-molybdenum alloy steel, mold steel S7 is a combination of special properties with high impact and toughness, and it is easy to process and heat treat. It is widely used in front and rear mold cores (HRC50-54), and is particularly suitable for making smaller slider inserts or front and rear mold inserts (HRC54-56). O1 steel is American standard non-deformable oil steel, the best oil hardening tool steel, heat treatment hardness up to HRC58-62, steel has good processing properties, good wear resistance, heat treatment performance and small dimensional deformation, but has weak toughness and corrosion resistance, and is widely used in auxiliary parts such as slider beading and wear plate.
    2. European mold steel
Steels commonly used in front and rear molds are DIN 1.2343 and DIN 1.2344, both of which are standard hot work tool steels commonly used in Europe. Heat treatment hardness of DIN 1.2343 is HRC50-54, suitable for molds and sliders with corrosive requirements, and DIN 1.2343 ESU for high polishing requirements. Heat treatment hardness of DIN 1.2344 is HRC48-52, which is suitable for molds and sliders with high wear resistance requirements, especially for plastics with high glass fiber content, and its toughness is slightly lower than DIN 1.2343. DIN 1.1730, equivalent to China's No. 45 or No. 50 carbon steel, is suitable for manufacture of plastic moulded parts that are not force or important. DIN 1.2312, this steel is pre-hardened steel, generally not suitable for heat treatment, but can be nitrided. It is often used to make mold A / B plates, support columns (heads) and top sticks. DIN 1.2767, suitable for making small inserts or other moving parts such as sliders and slanted tops. DIN 1.2842, used to make plastic moulded parts such as slider bead and wear plate, heat treated HRC48-52, and nitrided, nitride layer thickness is 0.2-0.4mm,
    3. Japanese mold steel
Japanese molds are usually based on soft molds. The most commonly used steel is NAK80, which is a pre-hardened steel, HRC38-41.
  • Pouring system design
European molds and North American molds require gating system to automatically cut off nozzles, and fully automatic injection moulding. Do not use mold release agents. Products and nozzles can be freely dropped or grabbed by robot. When it is necessary to feed top of product, hot runners are used. Due to expensive labor in Europe, it is generally not allowed to design a mold structure that requires manual trimming of nozzle. Sub-gate and Cowhorn gate can automatically cut off nozzle when it is ejected, and it is widely used. In automatic injection moulding production, Z-type pull needle is not used as much as possible. If it is produced by a robot, tapered pull needle is used to facilitate positioning of spout. Pin gate of three-plate mold is rarely used in Europe and North America, and design requires consent of guests.
  • Conclusion
In the past 10 years, pace of technological innovation in the field of molds has been significantly accelerated, and research and development of mold standard parts has become increasingly broad. Internationally renowned mold standard parts manufacturers such as HASCO, DME, DMS, MEUSBURGER and Lejiawen standards have continuously introduced new standard components. In the field of hot runners, MOLDMASTER and DME teamed up to create a European-style standard after DME acquired European EOC. Hot runner manufacturers such as EWIKON, SYNVENTIVE, and INCOE are also constantly introducing new standard parts. In Asia, MISUMI's standard parts are detailed to a number of different standards for each insert. On the other hand, our mold standard system has not been perfected, and there is no internationally renowned standard parts manufacturer. Our domestic mold standards lag behind actual use for decades, all of which require plastic moulding industry to seriously reflect.

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