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What should be paid attention to when accepting plastic molds?

Update:13-05-2020
Summary:

First, the appearance, scale and cooperation of molded […]

First, the appearance, scale and cooperation of molded products
1. The appearance of the product does not allow shortcomings: shortcomings, scorching, top white, white line, peak, blistering, whitening (or cracking, breaking), baking, wrinkles and other shortcomings.

2. Welding marks: Generally, the length of the circular perforated welding mark is not more than 5mm, and the length of the special-shaped perforated welding mark is less than 15mm. The strength of the welding mark can pass the functional safety test.

3. Shortening: Shortening is not allowed in the obvious area of ​​the appearance, and there is a slight shrinkage in the non-significant area (the dent is not felt).

4. Generally, the flatness of small products is less than 0.3mm. If there are device requirements, the device requirements should be ensured.

5. There should be no air lines or flowers in the obvious appearance, and the product should generally not have bubbles.

6. The geometric shape and scale precision of the product should conform to the requirements of a formal and useful drawing (or 3D file). The public service of the product should be based on the principle of public service. In public service, customers have requirements as required.

7. Product wall thickness: product wall thickness generally requires uniform wall thickness, non-uniform wall thickness should meet the requirements of drawings, public service should be -0.1mm based on mold characteristics.

8. Product cooperation: surface shell bottom shell cooperation: the appearance misalignment is less than 0.1mm, there must be no scratches, and the holes, shafts, and surfaces required for cooperation must ensure the cooperation interval and application requirements.

Second, the appearance of the mold

1. The content of the mold nameplate is intact, the characters are clear, and the arrangement is regular.

2. The nameplate should be fixed on the mold feet close to the template and the reference angle. The nameplate is fixed firmly and is not easy to peel off.

3. Cooling water nozzles should use plastic blocks to insert the water nozzles, and the customers have other requirements according to the requirements.

4. The cooling nozzle should not stick out of the mold

5. The cooling water nozzle needs to be processed with countersinks. The countersink diameter is 25mm, 30mm, 35mm, and the chamfering of the opening should be common.

6. The cooling water nozzle should have an entry and exit symbol.

7. Symbol English characters and numbers should be greater than 5/6, the orientation should be 10mm directly under the spout, and the handwriting should be clear, beautiful, regular and evenly spaced.

8. Mold accessories should not affect the lifting and storage of the mold. When the device is installed, there are exposed oil cylinders, water nozzles, pre-reset tissues, etc., which should be protected by supporting legs.

9. The support leg device uses screws to pass through the support leg and is fixed on the mold frame. The over-length support leg can be fastened on the mold frame with a machined externally threaded post.

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

11. The positioning ring should be fixed firmly. The diameter of the ring is generally 100mm and 250mm (depending on the model), and the positioning ring is 10 ~ 20mm higher than the bottom plate. Customers have other requirements outside.

12. The shape of the mold should meet the requirements of the specified injection molding machine.

13. The mold with orientation requirements of the device should indicate the device direction with arrows on the front template or the rear template. The word "UP" should be next to the arrow. The arrow and the text are both yellow and the word height is 50 mm.

14. There should be no pits, rust marks, remaining rings, water vapor, oil holes, etc., and defects that affect the appearance of the mold frame.

15. The mold should be easy to lift and transport. The parts of the mold must not be disassembled during lifting, and the lifting ring must not interfere with the water nozzle, oil cylinder, and pre-reset rod.

Third, mold information and hardness

1. The mold formwork should use a standard formwork that meets the specifications.

2. The materials of mold forming parts and pouring system (core, dynamic and fixed mold inserts, movable inserts, diverter cones, push rods, gate sleeves) are selected from materials with a performance higher than 40Cr.

3. When forming plastics that are easily corroded by the mold, the molded parts should be made of corrosion-resistant materials, or the molding surface should adopt anti-corrosion methods.

4. The hardness of moulded parts should not be less than 50HRC, or the hardness of surface hardening treatment should be higher than 600HV.

Fourth, ejection, reset, insert ferrule, pick up

1. The ejection should be smooth, free of stagnation and abnormal movements.

2. The surface of the inclined top should be polished, the inclined top surface is lower than the core surface.

3. The sliding parts should be provided with oil grooves, and the surface needs to be nitridized, and the surface hardness after treatment should be above HV700.

4. All jacks should have anti-rotation positioning, and each jack should be numbered.

5. Use the limit block to limit the ejection interval.

6. Standard parts should be used for the reset spring, and both ends of the spring should not be polished or cut off.

7. The slider and core pulling should have travel limit. The small slider is limited by the tension spring. When the tension spring is inconvenient, the wave screw can be used; the oil cylinder core pulling must have a stroke switch.

8. The inclined core guide is generally used for the core pulling of the slider, and the viewpoint of the inclined guide pole should be 2 ° ~ 3 ° smaller than the viewpoint of the locking surface of the slider. If the stroke of the slider is too long, the cylinder should be used for extraction.

9. When the end face of the core part of the oil cylinder is covered, the oil cylinder should be self-locking.

10. There should be wear-resistant plates under the large slider with the width of the slider exceeding 150 mm. The material of the wear-resistant plate should be T8A. The hardness after heat treatment is HRC50 ~ 55. The wear-resistant plate is 0.05 ~ 0.1 mm higher than the large surface. Open the oil tank.

11. The top rod should not move up and down in series.

12. Add a barb on the top bar. The direction of the barb should be kept the same. The barb can be easily removed from the product.

13. The cooperative gap between the jack hole and the jack, the length of the seal section, and the appearance roughness of the jack hole should be in accordance with the requirements of relevant enterprise specifications.

14. The product should be removed by the operator.

15. When the product is ejected, it is easy to follow the inclined top, and the top rod should be grooved or etched.

16. The top block fixed on the top rod should be strong and firm, the non-molded parts around should be processed with a slope of 3 ° ~ 5 °, and the periphery of the lower part should be chamfered.

17. There should be no iron debris in the oil passage holes on the mold frame.

18. The end face of the return rod is smooth without spot welding. There is no gasket at the bottom of the embryo head, spot welding.

19. The gate slide of the three-plate mold gate plate is smooth, and the gate plate can be easily pulled apart.

20. The limit levers of the three-plate die should be placed on both sides of the direction of the mold device, or a pull plate should be added outside the die frame to prevent interference between the limit lever and the operator.

21. The air passage of the oil passage should be smooth, and the hydraulic ejection reset should be in place.

22. The bottom of the guide sleeve should have an exhaust port.

23. The positioning pin device must have no gaps.

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