Manufacturing acceptance standard for precision plastic mould

- Oct 23, 2019-




To make a set of precision mold, we should not only have a high level of mold design and precision processing technology, but also have a precise concept of mold development. What is the concept of precise mold development?

In fact, the mold is not about how much you do, but whether your mold development pursues the perfection of details and reliable standards. There is no "almost" concept in this process.




I. mold appearance



1. The contents of mold nameplate are complete, the characters are clear and arranged in order.

2. The nameplate shall be fixed on the mold foot near the template and reference angle. The nameplate is fixed reliably and not easy to peel off.

3. The cooling water nozzle shall be plastic block water faucet, if otherwise required by the customer, it shall comply with the requirements.

4. The cooling water nozzle shall not extend out of the mold base surface.

5. The cooling water nozzle needs to be processed with counterbore with diameter of 25mm, 30mm and 35mm. The chamfer of the orifice shall be the same.

6. The cooling water nozzle shall be marked with inlet and outlet marks.

7. The English characters and numbers of the mark shall be greater than 5 / 6, and the position shall be 10 mm below the water nozzle. The handwriting shall be clear, beautiful, neat and even.

8. The mold accessories shall not affect the lifting and storage of the mold. During installation, there are exposed oil cylinder, water nozzle, pre reset mechanism, etc. below, which shall be protected by support leg.

9. The installation of the support leg shall be fixed on the formwork with screws passing through the support leg, and the long support leg can be fastened on the formwork with the processed external thread column.

10. The ejection hole size of the mold shall meet the requirements of the specified injection molding machine. Except for the small mold, it cannot be ejected with only one center.

11. The locating ring shall be fixed reliably. The diameter of the ring is 100mm and 250mm. The locating ring is 10-20mm higher than the bottom plate. Unless otherwise required by the customer.

12. The overall dimension of the mold shall meet the requirements of the specified injection molding machine.

13. For the mould installed with direction requirements, the installation direction shall be indicated with arrows on the front or rear formwork, and the words "up" shall be set beside the arrows. The arrows and words shall be yellow and the height of the words shall be 50mm.

14. The surface of the mold base shall be free of pits, rust, redundant rings, water vapor in and out, oil holes and other defects affecting the appearance.

15. The mold shall be convenient for hoisting and transportation. During hoisting, the mold parts shall not be disassembled, and the lifting ring shall not interfere with the water nozzle, oil cylinder, pre reset rod, etc.





II. Mold material and hardness


1. The mold base shall be the standard mold base conforming to the standard.

2. Materials with properties higher than 40Cr shall be used for mold forming parts and pouring system (core, movable and fixed mold insert, movable insert, shunt cone, push rod and gate sleeve).

3. When forming the plastic that is easy to corrode the mold, the forming parts shall be made of corrosion-resistant materials, or the forming surface shall be provided with anti-corrosion measures.

4. The hardness of moulded parts shall not be lower than 50HRC, or the hardness of surface hardening treatment shall be higher than 600hv.




III. ejection, reset, core pulling and inserting, and parts taking


1. The ejection shall be smooth, free of jamming and abnormal sound.

2. The inclined top surface shall be polished, and the inclined top surface shall be lower than the core surface.

3. The sliding parts shall be provided with oil groove, and the surface shall be nitrided, and the surface hardness after treatment shall be above hv700.

4. All jacking rods shall have stop rotation positioning, and each jacking rod shall be numbered.

5. The ejection distance shall be limited by limit block.

6. The return spring shall be standard parts, and both ends of the spring shall not be polished or cut.

7. The slide block and core pulling shall be provided with stroke limit, and the small slide block shall be provided with spring limit. When the spring is inconvenient to be installed, it can be provided with wave screw; the core pulling of oil cylinder must be provided with stroke switch.

8. Generally, the sliding block core pulling adopts the inclined guide pillar, and the angle of the inclined guide pillar shall be 2 ° ~ 3 ° smaller than the angle of the locking surface of the sliding block. If the stroke of sliding block is too long, oil cylinder shall be used for drawing.

9. When the end face of the core pulling forming part of the oil cylinder is covered, the oil cylinder shall be equipped with a self-locking mechanism.

10. There should be a wear-resistant plate under the large slider with a width of more than 150 mm. The wear-resistant plate material should be T8A. After heat treatment, the hardness is hrc50-55. The wear-resistant plate is 0.05-0.1 mm higher than the large surface, and the oil tank should be opened.

11. The ejector rod shall not move up and down in series.

12. Add barb on the top bar, the direction of barb shall be consistent, and barb is easy to be removed from products.

13. The fitting clearance between the ejector pin hole and the ejector pin, the length of the sealing section, and the surface roughness of the ejector pin hole shall meet the requirements of relevant enterprise standards.

14. The products shall be easy for operators to take down.

15. When the product is ejected, it is easy to follow the inclined roof, and the top bar shall be provided with grooves or etchings.

16. The top block fixed on the top bar shall be firm and reliable. The non formed part around shall be processed with a slope of 3 ° ~ 5 °, and the lower part shall be chamfered.

17. There shall be no iron filings and sundries in the oil way hole on the mold base.

18. The end face of return rod shall be flat without spot welding. No gasket at the bottom of embryo head, spot welding.

19. The guide of the gate plate of the three plate mold slides smoothly, and the gate plate is easy to be pulled apart.

20. The limit pull rod of the three plate mold shall be arranged on both sides of the mold installation direction, or a pull plate shall be added to the mold base to prevent the interference between the limit pull rod and the operator.

21. The oil passage passage shall be smooth, and the hydraulic ejection reset shall be in place.

22. The bottom of the guide sleeve shall be provided with an air outlet.

23. There shall be no clearance during the installation of locating pin.

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