Injection mold acceptance is our frequent work. How to conduct acceptance and which items to accept can give a more comprehensive understanding of status of a set of molds. Following chapters will be divided into several chapters for detailed introduction.

 

1. Defects are not allowed on product surface: lack of material, burnt, top white, white line, peak, blister, pull white (or crack, pull off), wrinkles.
2. Weld mark: Generally, length of weld mark of circular perforation is not more than 5mm, and length of weld mark of special-shaped perforation is less than 15mm. Weld mark strength can pass functional safety test.
3. Shrinkage: Shrinkage is not allowed in obvious places on appearance surface, and slight shrinkage is allowed in inconspicuous places (no dents can be felt).
4. Generally, surface unevenness of small products is less than 0.3mm, and assembly requirements must be guaranteed if there are assembly requirements.
5. There should be no air marks or material flowers in obvious appearance, and product should generally not have bubbles.
6. Geometric shape and size accuracy of product should meet requirements of formal and effective mold opening drawings (or 3D files). Product tolerance should be based on tolerance principle. Shaft size tolerance is negative tolerance, and hole size tolerance is positive tolerance. If customer has requirements, follow requirements.
7. Product wall thickness: Product wall thickness is generally required to be average wall thickness, and non-average wall thickness should meet requirements of drawings.
8. Product matching
Face shell and bottom shell matching: Surface misalignment is less than 0.1mm, and there should be no scratching phenomenon. Holes, shafts, surfaces with matching requirements must ensure matching interval and use requirements.

1. Content of mold nameplate is complete, characters are clear, and arrangement is neat.
2. Nameplate should be fixed on mold foot near mold plate and reference angle. Nameplate is fixed reliably and not easy to peel off.
3. Cooling water nozzle should use a plastic quick-plug water nozzle. If customer has other requirements, follow requirements.
4. Cooling nozzle should not extend beyond mold surface
5. Cooling nozzle needs to be processed with countersunk holes. Diameter of countersunk hole is 25mm, 30mm, and 35mm. Hole should be chamfered and chamfers should be consistent.
6. Cooling nozzle should have inlet and outlet marks.
7. English characters and numbers marked should be greater than 5/6, and position should be 10mm directly below nozzle. Handwriting should be clear, beautiful, neat, and evenly spaced.
8. Mold accessories should not affect hoisting and storage of mold. During installation, there are exposed oil cylinders, nozzles, pre-reset mechanisms, etc. below, which should be protected by support legs.
9. Installation of support legs should be fixed to mold frame with screws through support legs. Overlong support legs can be processed with external threaded columns to fasten them to mold frame.
10. Size of mold ejection hole should meet specified injection molding machine requirements. Except for small molds, only one center ejection cannot be used.
11. Positioning ring should be fixed reliably, with a diameter of 100mm and 250mm, and positioning ring should be 10~20mm higher than bottom plate. Unless otherwise required by customer.
12. Mold dimensions should meet requirements of specified injection molding machine.
13. Mold with directional requirements should be marked with an arrow on the front or rear template to indicate installation direction. There should be a "UP" next to arrow. Arrow and text are both yellow, and height is 50mm.
14. Mold frame surface should not have pits, rust, extra rings, water inlet and outlet holes, oil holes, etc., as well as defects that affect appearance.
15. Mold should be easy to hoist and transport. Mold parts must not be disassembled during hoisting, and rings must not interfere with faucet, oil cylinder, pre-reset rod, etc.

 

1. Mold frame should use a standard mold frame that meets standards.
2. Materials of mold forming parts and pouring system (core, movable mold insert, movable insert, diverter cone, push rod, gate sleeve) are made of materials with performance higher than 40Cr. Core and cavity materials specified by customer are in accordance with customer requirements.
3. When molding plastics that are easily corroded by the mold, molded parts should be made of corrosion-resistant materials, or anti-corrosion measures should be taken on their molding surfaces.
4. Hardness of mold forming parts should not be less than 50HRC, or hardness of surface hardening treatment should be higher than 600HV.

1. Ejection should be smooth, without jamming, and without abnormal sound.
2. Lifter surface should be polished, and lifter surface should be lower than core surface.
3. Sliding parts should have oil grooves, and surface should be nitrided. Surface hardness after treatment is above HV700.
4. All ejectors should have anti-rotation positioning, and each ejector should be numbered.
5. Ejection distance should be limited by limit blocks.
6. Standard parts should be used for reset springs, and both ends of springs should not be polished or cut off.
7. Sliders and core pullers should have travel limits. Small slides are limited by springs. When springs are inconvenient to install, ball screws can be used; cylinder core pullers must have travel switches.
8. Slider core pullers generally use inclined guide pins, and angle of inclined guide pins should be 2°~3° smaller than angle of slider locking surface. If slider stroke is too long, a cylinder should be used for pulling.
9. When end face of cylinder core pull molding part is covered, cylinder should be equipped with a self-locking mechanism.
10. Large slides with a width of more than 150mm should have a wear-resistant plate under them. Wear-resistant plate material should be T8A, and hardness after heat treatment is HRC50~55. Wear-resistant plate is 0.05~0.1mm higher than large surface, and an oil groove is opened.
11. Ejector should not move up and down.
12. Add a barb to ejector, and direction of barb should be consistent, so that barb can be easily removed from product.
13. Clearance between ejector hole and ejector, length of sealing section, and surface roughness of ejector hole should comply with requirements of relevant enterprise standards.
14. Product should be easy for operator to remove.
15. Product is easy to follow lifter when ejecting, and ejector should be grooved or etched.
16. Ejector block fixed on ejector should be firm and reliable, non-molding parts around should be processed with a slope of 3°~5°, and lower periphery should be chamfered.
17. There should be no iron filings or debris in oil passage hole on mold frame.
18. End face of return rod is flat and there is no spot welding.
19. Guide sliding of three-plate mold gate plate is smooth, and gate plate is easy to pull open.
20. Three-plate mold limit rod should be arranged on both sides of mold installation direction, or a pull plate should be added to mold frame to prevent limit rod from interfering with operator.
21. Oil and air channels should be smooth, and hydraulic ejection reset should be in place.
22. An exhaust port should be opened at the bottom of guide sleeve.
23. There should be no gap when installing positioning pin.

 

For futher reading, please refer to Injection mold acceptance items and requirements 2.