Injection mold must be so acceptance dare to use!

- May 16, 2019-

I. appearance, size and coordination of molding products

1. No defects are allowed on the surface of the product: lack of material, burning, top white, white thread, top peak, foaming, whitening (or cracking, breaking), drying, wrinkles and other defects.

2. Welding marks: generally, the length of circular welding marks shall not be more than 5mm, and the length of special-shaped welding marks shall be less than 15mm, and the welding marks shall be strong enough to pass the functional safety test.

3. Shrinkage: no shrinkage is allowed in the obvious part of the surface, and slight shrinkage is allowed in the non-obvious part (no indentation).

4. General small products with planar unflatness less than 0.3mm, assembly requirements shall be ensured if there are assembly requirements.

5. There should be no air lines or material flowers in the obvious appearance, and generally there should be no air bubbles in the product.

6. The geometric shape, size and precision of the product shall meet the requirements of formal and effective mold opening drawings (or 3D files). The tolerance of the product shall be in accordance with the tolerance principles.

7. Product wall thickness: the product wall thickness is generally required to be average, the non-average wall thickness shall meet the requirements of the drawing, and the tolerance shall be -0.1mm according to the characteristics of the mold.

8. Product matching: surface shell and bottom shell matching: the surface dislocation is less than 0.1mm, and there is no scraping phenomenon. Holes, shafts and surfaces with matching requirements shall ensure the matching interval and use requirements.

Ii. Mold appearance

1. The content of the mold nameplate is complete, and the characters are clear and neatly arranged.

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

3. The cooling water nozzle shall be made of plastic block, otherwise as required by customers.

4. Cooling nozzle should not extend out of the surface of the formwork

5. The cooling water nozzle shall be machined with sinker holes, the diameter of which shall be 25mm, 30mm and 35mm, and the chamfering Angle of the orifice shall be consistent.

6. Cooling water nozzles shall have inlet and outlet marks.

7. The marked English characters and Numbers shall be greater than 5/6, and the position shall be 10mm directly below the nozzle, and the handwriting shall be clear, beautiful, neat and evenly spaced.

8. The mold accessories shall not affect the lifting and storage of the mold.When installing, there are exposed oil cylinder, water nozzle, pre-reset mechanism, etc., which should be protected by supporting legs.

9. The mounting of the support leg shall be fixed on the die frame through the support leg with screws. If the support leg is too long, it can be fixed on the die frame with cart-machined posts with external threads.

10. The size of the ejection hole of the mold shall meet the requirements of the specified injection molding machine. Except for small molds, it is not allowed to use only one center for ejection.

11. The positioning ring shall be fixed and reliable. The diameter of the ring is usually 100mm or 250mm (depending on different models).Unless otherwise requested by the customer.

12. The overall dimensions of the molds shall meet the requirements of the specified injection molding machine.

13. The installation direction of the molds with direction requirements shall be marked with arrows on the front template or the back template. The words "UP" shall be beside the arrows.

14. The surface of the formwork shall be free from 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. The mold parts shall not be removed during hoisting, and the hoisting ring shall not interfere with nozzles, oil cylinders, pre-reset rods, etc.

Mold material and hardness

1. The mold frame shall meet the standard mold frame.

2. Mold forming parts and casting system (core, moving fixed mold insert, movable insert, split cone, push rod and sprue sleeve) adopt materials with performance higher than 40Cr.

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

4. The hardness of molding parts shall be no less than 50HRC, or the hardness of surface hardening treatment shall be higher than 600HV.

Iv. Ejection, reset, core pulling and core pulling

1. The ejection should be smooth, without stuck or abnormal sound.

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

3. Oil groove shall be set for sliding parts, and the surface shall be nitrided, and the surface hardness shall be above HV700 after treatment.

4. All jacks shall have stop stop positioning and each jacking shall be numbered.

5. Limit block shall be applied for the jacking distance.

6. Standard parts shall be selected for the reset spring. The two ends of the spring shall not be polished or cut off.

7. The slide block and core pulling should have travel limit. The small slide block should have spring limit.Cylinder core pulling must have a stroke switch.

8. Slide block core-pulling generally adopts the inclined guide pillar, Angle of oblique guide pillar should be smaller than the slider locking surface Angle 2 ° ~ 3 °.If the stroke of the slide block is too long, the oil cylinder shall be used for extraction.

9. When the end face of the core-pulling forming part of the oil cylinder is coated, a self-locking mechanism shall be added to the oil cylinder.

10. There should be wear-resistant plate under the large slider with a width of more than 150mm. The wear-resistant plate material should be T8A, whose hardness is hrc50-55 after heat treatment.

11. The jacking rod shall not be moved up and down in series.

12. Add barbs on the ejector rod. The direction of barbs should be consistent.

13. The matching clearance between rod jacking holes and rod jacking holes, the length of the sealing section, and the surface roughness of rod jacking holes shall be in accordance with relevant enterprise standards.

14. The product should be convenient for operators to remove.

15. Products are easy to follow the inclined jacking out, the jacking rod should be grooved or etched.

16. On the top bar on the top piece, should be solid and reliable, and around the molding part should be processed 3 ° ~ 5 ° slope, the lower surrounding should be chamfer.

17. There should be no iron debris in the oil path hole of the mold frame.

18. The end face of the return rod is smooth without spot welding.Blank head bottom without gasket, spot welding.

19. The guide slide of the gate plate of the three-plate mold is smooth, and the gate plate is easy to be pulled away.

20. The limit pull rod of the three-plate mould should be arranged on both sides of the direction of mould installation or on the outside of the mould frame to prevent interference between the limit pull rod and the operator.

21. The oil channel should be smooth and the hydraulic jacking reset should be in place.

22. Vent shall be opened at the bottom of guide sleeve.

23. The positioning pin shall be installed without clearance.

V. cooling and heating system

1. The cooling or heating system should be fully unimpeded.

2. The seal should be reliable, and there should be no leakage in the system under the pressure of 0.5mpa, which is easy to repair.

3. The size and shape of the sealing groove on the mold frame shall meet the relevant standard requirements.

4. Grease the sealing ring and place it higher than the surface of the mold frame.

5. Water and oil flow channel spacers shall be made of materials that are not prone to corrosion.

6. Centralized water supply shall be adopted for front and rear molds.

7. The diameter of the cooling channel is between 8 and 12mm.

Pouring system

1. Gate setting should not affect the appearance of the product and meet the requirements of product assembly.

2. The section and length of the flow channel shall be designed reasonably, the process shall be shortened as far as possible on the premise of guaranteeing the forming quality, the cross-sectional area shall be reduced to shorten the filling and cooling time, and the losses of the casting system shall be minimized.

3. Part of the cross-section of the three-plate mold runner on the back of the front formwork shall be trapezoidal or semicircular.

4. The three plate mould has broken material on the gate plate, the diameter of the gate entrance shall be less than 3 mm, and the ball head has a 3 mm deep step in the gate plate.

5. The ball head pull rod should be fixed reliably, which can be pressed under the positioning ring. It can be fixed with headless screws or pressed with pressure plate.

6. The sprue and runner should be machined according to the size requirements of the drawing, and manual grinding machine is not allowed.

7. Gate gate shall be in accordance with the requirements of the specification.

8. There should be an extension at the front end of the shunt as a cold hole.

9. Pull rod z-shaped inverted button should have smooth transition.1

0. The shunt passage on the parting surface shall be round and the front and rear dies shall not be misplaced.

11. The latent gate on the ejector rod shall have no surface shrinkage.

12. Diameter and depth of cold hole of transparent products shall meet the design standards.

13. The material is easy to remove, and there is no gate mark on the appearance of the product, and there is no residual material at the assembly place of the product.

14. Bend hook latent gate, two parts of inserts should be nitrided, surface hardness up to HV700.

Vii. Forming part, parting surface and exhaust groove

1. Front and rear molds shall not have uneven surface, pits, rust and other defects affecting the appearance.

2. The insert shall be matched with the die frame, and the surrounding rounded corners shall have a clearance less than 1mm.

3. The parting surface shall be kept clean and tidy. No portable grinding wheel shall be used to avoid the air.

4. Vent depth should be less than the overflow value of the plastic.

5. Embedded parts should be in place for smooth installation and reliable positioning.

6. The inserts and cores shall be located and fixed reliably, the circular parts shall have stop rotation, and copper and iron sheets shall not be padded under the inserts.

7. The end face of the ejector rod is consistent with the core.

8. Front and rear molding parts are free from defects such as overturning and chamfering.

9. Tendon ejection should be smooth.

10. For products with multi-cavity molds, the left and right parts shall be symmetrical, and L or R shall be indicated. If customers have requirements on the location and size, they shall meet the requirements of customers.

11. The locking surface of the mold frame shall be grinded and matched in place, with more than 75% of the area touched.

12. The jacking rod shall be arranged near the side wall and beside the ribs and boss, and a larger jacking rod shall be used.

13. For the same parts, Numbers 1, 2 and 3 shall be indicated.

14. The colliding and piercing surfaces, intercalating and parting surfaces shall be developed and matched in place.

15. Parting surface sealing part shall meet the design standard.10~20mm for the following medium molds, 30~ 50mm for the large molds, and the rest parts shall be machined to avoid air.

16. The leather grain and sandblasting shall meet the customer's requirements evenly.

17. For products with appearance requirements, the screws on the products shall have anti-shrink measures.

18. For screw posts with a depth of more than 20 mm, pipe jacking shall be used.

19. The wall thickness of products shall be even, and the deviation shall be controlled below 0.15mm.

20. The width of the reinforcement shall be less than 60 percent of the thickness of the outer wall

21. The core insert on the inclined roof and sliding block should be fixed in a reliable way.

22. Front die insert rear die or rear die insert front die, the surrounding slope should be locked and machined to avoid air.

Viii. Injection molding production process

1. The mold should have the stability of injection molding production and the repeatability of process parameter adjustment within the normal injection molding process conditions.

2. The injection pressure during mold injection production should be generally less than 85% of the rated maximum injection pressure of the injection molding machine.

3. The injection speed in the mold injection production shall be no less than 10% of the rated maximum injection speed or more than 90% of the rated maximum injection speed.

4. The holding pressure of the injection mold should be generally less than 85% of the actual maximum injection pressure.

5. The clamping force of the injection mold should be less than 90% of the rated clamping force of the applicable model.

6. In the process of injection molding, the product and nozzle material should be easily and safely removed (generally no more than 2 seconds each).

7. The molds with insert products should be easy to install and reliable to fix during production.

Ix. Packaging and transportation

1. Mold cavity shall be cleaned and sprayed with anti-rust oil.

2. The sliding parts shall be lubricated.

3. Gate sleeve inlet shall be sealed with grease.

4. Clamping plate shall be installed in the mold, and the specifications shall meet the design requirements.

5. Spare parts and consumable parts shall be complete with a detailed list and the name of the supplier

6. The inlet and outlet of mold water, liquid, gas and electricity shall be sealed to prevent foreign bodies from entering;

7. Spray paint on the outer surface of the mold, as required by customers.

8. The molds shall be moisture-proof, water-proof and anti-knock packaging, as required by customers.

9. Mold product drawings, structure drawings, cooling and heating system drawings, hot runner drawings, parts and mold material supplier details, operation instructions, mold test report, ex-factory inspection certificate, and electronic documents shall be complete.