What issues should you pay attention to when accepting plastic molds?
First, the appearance, scale and cooperation of molded products
1. The appearance of the product does not agree with the shortcomings: lack of material, burnt, white, white line, peak, foaming, white (or cracking, breaking), baking, wrinkles and other shortcomings.
2. Weld marks: Generally, the length of the circular perforated weld line is not more than 5mm, and the length of the shaped perforated weld line is less than 15mm. The strength of the weld line can be tested by functional safety.
3. Shorten: The appearance is obviously not allowed to be shortened, and the obvious is not allowed to shrink slightly (the hand does not feel dents).
4. Generally, the flatness of small products is less than 0.3mm, and the requirements of the device are required to ensure the requirements of the device.
5. The appearance of the place can not be air-grained, material flowers, the product generally can not have bubbles.
6. The geometric shape of the product, the accuracy of the scale should meet the requirements of the officially useful open mold drawing (or 3D file). The product public service should be based on the principle of public service, the axis scale public service is negative public service, and the hole class scale is public service. In the public service, the customer has the required requirements.
7. Product wall thickness: The product wall thickness generally requires uniform wall thickness, and the non-uniform wall thickness should meet the requirements of the drawings. The public service should be -0.1mm according to the mold characteristics.
8. Product cooperation: cooperation between the shell and the bottom shell: the misalignment of the outer surface is less than 0.1mm, there is no shaving phenomenon, and the holes, shafts and surfaces with cooperation requirements should ensure the cooperation interval and application requirements.
Second, the appearance of the mold
1. The nameplate of the mold is in good condition, the characters are clear, and the arrangement is regular.
2. The nameplate should be fixed to the mold base close to the template and the reference angle. The nameplate is fixed and not easy to peel off.
3. The cooling nozzle should be a plastic block nozzle, as required by the customer.
4. The cooling nozzle should not protrude from the outer surface of the mold base
5. The cooling nozzle needs to be processed with countersunk holes. The diameter of the counterbore is 25mm, 30mm, 35mm. The chamfering of the hole and the chamfer should be common.
6. The cooling nozzle should have an entry and exit symbol.
7. The symbolic English characters and numbers should be greater than 5/6, and the orientation should be 10mm below the water nozzle. The handwriting should be clear, beautiful, regular and evenly spaced.
8. Mold parts should not affect the lifting and storage of the mold. There should be exposed cylinders, faucets, pre-reset tissue, etc. under the device, and should have support leg protection.
9. The support leg device is fixed to the formwork by screws through the support legs, and the too long support legs can be fastened to the formwork by the machined externally threaded columns.
10. The size of the die ejector hole should meet the requirements of the specified injection molding machine. Except for the small mold, 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 above the bottom plate. The customer has other requirements.
12. The mold dimensions should match the requirements of the specified injection molding machine.
13. The mold with direction requirements should be marked with arrows on the front or rear template. The arrow should have “UP” next to the arrow. The arrow and text are yellow and the height is 50 mm.
14. The appearance of the formwork should not have pits, rust, remaining rings, water vapor, oil holes, etc., as well as shortcomings that affect the appearance.
15. The mold should be easy to hoist and transport, and the mold parts must not be disassembled during lifting. The lifting ring must not interfere with the water nozzle, oil cylinder and pre-reset rod.
Third, mold data and hardness
1. The mold formwork should be a standard formwork that conforms to the specifications.
2. Mold molding parts and casting system (core, moving mold insert, movable insert, splitter cone, push rod, sprue sleeve) data selection performance is higher than 40Cr.
3. When molding plastics that are corrosive to 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 the molded parts of the mold should not be lower than 50HRC, or the hardness of the external hardening treatment should be higher than 600HV.
Fourth, ejector, reset, thrust ferrule, take-up
1. It should be smooth, no stuck, and no abnormal movement when it is ejected.
2. The top of the slanted top should be polished, and the inclined top surface is lower than the core surface.
3. The sliding part should be opened with oil groove, and the outer surface should be nitrided. The hardness of the outer surface after treatment is HV700 or above.
4. All rams should have a non-rotation position and each ram should be numbered.
5. The ejection interval is limited by the limit block.
6. The reset spring should be selected with standard parts, and the ends of the spring should not be ground or cut.
7. The slider and the core should have the travel limit. The small slider is limited by the tension spring. When the spring is inconvenient, the wave screw can be used. The cylinder core must have a travel switch.
8. The slider core is generally selected as the oblique guide column, and the viewpoint of the inclined guide column should be 2°~3° smaller than the viewpoint of the slider locking surface. If the stroke of the slider is too long, the cylinder should be extracted.
9. When the end face of the cylinder core forming part is covered, the cylinder should be self-locking.
10. There should be wear plates under the large slider with the width of the slider exceeding 150 mm. The material of the wear plate should be T8A. After heat treatment, the hardness is HRC50~55, and the wear plate is 0.05~0.1 mm higher than the large surface. Open the oil tank.
11. The ejector pin should not be strung up and down.
12. Add barbs to the ejector pin. The direction of the barbs should be kept in common. The barbs are easy to remove from the product.
13. The cooperation gap between the ejector hole and the ejector pin, the length of the sealing section, and the appearance roughness of the ejector hole shall be in accordance with the relevant enterprise specifications.
14. The product should be suitable for the operator to take it off.
15. When the product is ejected, it is easy to follow the oblique top, and the ejector pin should be grooved or etched.
16. The top block fixed on the ejector pin should be firm and firm, and the non-formed part should be processed by 3°~5°, and the lower part should be chamfered.
17. There should be no iron filings in the oil passage hole on the mold base.
18. The end of the return rod is flat and there is no spot welding. There is no gasket at the bottom of the embryo, spot welding.
19. The three-plate mold gate plate slides smoothly, and the gate plate is easy to pull open.
20. The three-plate mold limit rod should be placed on both sides of the mold device direction, or the pull plate should be added outside the mold frame to prevent the limit rod from interfering with the operator.
21. The oil passage should be smooth and the hydraulic ejector reset should be in place.
22. The exhaust port should be opened at the bottom of the guide sleeve.
23. The locating pin device must not have a gap.
5. Cooling and heating system
1. The cooling or heating system should be fully ventilated.
2. The seal should be firm, the system should not leak under the pressure of 0.5MPa, and it is easy to overhaul.
3. The dimensions and shape of the sealing groove opened on the formwork shall conform to the relevant specifications.
4. When the sealing ring is placed, it should be buttered and placed higher than the mold surface.
5. Water and oil flow passage spacers should be selected from materials that are not easily corroded.
6. The front and rear molds should be collected and watered.
7. The diameter of the cooling channel is between 8 and 12 mm.
Sixth, the pouring system
1. The gate setting should not affect the appearance of the product and meet the product installation.
2. The cross-section and length of the runner should be designed reasonably. The process should be shortened as much as possible to ensure the forming quality, and the cross-sectional area should be reduced to shorten the filling and cooling time. The plastics lost in the casting system should be the least.
3. The partial section of the three-plate mold runner on the reverse side of the front template shall be trapezoidal or semi-circular.
4. The three-plate mold has a material break on the gate plate. The diameter of the runner inlet should be less than 3 mm. The ball head has a step of 3 mm deep into the gate plate.
5. The ball pull rod should be firmly fixed, can be pressed under the positioning ring, can be fixed by headless screws, or can be pressed by the pressure plate.
6. The gates and runners shall be machined according to the requirements of the drawings, and shall not be allowed to be processed by hand.
7. The gate gate should be in accordance with the specifications.
8. The front end of the runner should have an extension as a cold pocket.
9. The Z-shaped inverted buckle of the pulling rod should have a slippery transition. 1
0. The splitter on the parting surface should be circular, and the front and rear modes should not be misaligned.
11. The ambush gate on the ejector rod should have no external shortening.
12. The diameter and depth of the cold hole of the transparent product should conform to the design specifications.
13. The material is easy to remove, the appearance of the product has no gate marks, and there is no residual material at the product device.
14. Bent hook ambush gate, the two parts of the block should be nitrided, the appearance hardness reaches HV700.
7. Forming part, parting surface, exhaust groove
1. There should be no defects such as unevenness, pits, rust and other appearances on the front and rear molds.
2. The inserts cooperate with the mold frame, and the rounded corners should have a gap of less than 1mm.
3. The parting surface is kept clean and tidy, and there is no portable grinding wheel to avoid the air, and the sealing part has no depression.
4. The depth of the venting groove should be less than the overflow value of the plastic.
5. Inserts should be placed in place, placed smoothly and securely positioned.
6. Inserts, inserts, etc. should be firmly positioned and fixed, the circular parts have a rotation stop, and the copper pieces and iron pieces are not placed under the inserts.
7. The end face of the ejector pin is shared with the core.
8. There are no disadvantages such as reverse buckle and chamfer in the front and rear mold forming parts.
9. The ribs should be smooth out.
10. Multi-cavity mold products, the left and right parts are symmetrical, should be marked with L or R. If the customer has requirements on the orientation and scale, it should meet the customer's requirements. Generally, it will be added without affecting the appearance and installation. The font size is 1/8. .
11. The mold frame locking surface should be in place and more than 75% of the area will be encountered.
12. The ejector pin should be placed close to the side wall and beside the ribs and bosses, and use a larger ram.
13. For the same piece, the numbers 1, 2, 3, etc. should be noted.
14. Each touch surface, insert surface, and parting surface should be in place.
15. The parting surface sealing part should conform to the design specifications. The medium-sized mold is 10~20mm, the large mold is 30~50mm, and the rest is machined to avoid the air.
16. Skin and sandblasting should reach the customer's requirements evenly.
17. The appearance of the required product, the screws on the product should have a shrink-proof method.
18. The top of the screw column with a depth of more than 20 mm should be used.
19. The wall thickness of the product should be uniform and the error should be controlled below ±0.15mm.
20. The width of the rib should be less than 60% of the wall thickness of the exterior surface.
21. The sloping roof and the insert on the slider should have a firm fixing method.
22. The front die pierces the back die or the back die into the front die, and the bevel should be locked around the machine and machined to avoid the air.
Eight, injection molding production process
1. The mold should have the stability of injection molding and the repeatability of process parameter adjustment within the normal injection molding process conditions.
2. The injection pressure at the time of mold injection is generally less than 85% of the maximum maximum injection pressure of the injection molding machine.
3. The injection speed of the mold injection molding, the injection speed of three quarters of the stroke is not less than 10% of the extra maximum injection speed or exceeds 90% of the extra maximum injection speed.
4. The holding pressure at the time of mold injection is generally less than 85% of the maximum injection pressure.
5. The clamping force of the mold injection molding should be less than 90% of the additional clamping force of the applicable model.
6. In the process of injection molding, the removal of the product and the nozzle material should be simple and safe (the time generally does not exceed 2 seconds).
7. The mold with insert products is convenient for the inserting device when the production is made, and the insert is fixed firmly.
Nine, packaging, shipping
1. The mold cavity should be cleaned and sprayed with anti-rust oil.
2. The sliding parts should be lubricated.
3. The sprue bush inlet is sealed with grease.
4. The mold should be equipped with a locking die, and the specification meets the design requirements.
5. Spare parts for spare parts should be complete with a list and supplier name
6. The import and export of mold water, liquid, gas and electricity shall be sealed by sealing method to prevent foreign matter from entering;
7. The exterior and exterior of the mold are sprayed with paint, and the customer has the required requirements.
8. The mold should be moisture-proof, waterproof, and bump-proof packaging, as required by the customer.
9. Mold product drawings, structural drawings, cooling and heating system drawings, warm runner drawings, spare parts and mold data supplier details, operating instructions, test mode statement, factory inspection certificate, electronic documents should be complete.