To create a set of molds that can be called tall, not only must have a high level of mold design and precision processing, but also must have a sophisticated concept of mold development. What is the concept of precision mold development? There are many people who disagree, how do they think that they have done so many molds without precision? In fact, the mold is not about how much to do, but whether your mold development pursues the excellence of the details, whether to pursue reliable standards, this process must not allow the concept of "almost".
First, the appearance of the mold
1. The mold nameplate is complete in content, clear in characters and neatly arranged.
2. The nameplate should be attached to the mold foot near 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 beyond the surface of the mold base.
5. The cooling nozzle needs to be machined with countersinks. The diameter of the counterbore is 25mm, 30mm and 35mm. The chamfering of the orifice should be consistent.
6. The cooling nozzle should have an ingress and exit mark.
7. The marked English characters and numbers should be greater than 5/6, and the position should be 10mm directly below the water nozzle. The writing should be clear, beautiful, neat and evenly spaced.
8. Mold parts should not affect the lifting and storage of the mold. There should be exposed cylinders, faucets, pre-reset mechanisms, etc. under the installation, and should have support leg protection.
9. Mounting of the support legs The application screws are fixed to the formwork 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 and reliable. The diameter of the ring is 100mm and 250mm. The positioning ring is 10~20mm above the bottom plate. Except as otherwise requested by the customer.
12. The dimensions of the mould shall be in accordance with the requirements of the specified injection molding machine.
13. Install the mold with direction requirements. The installation direction should be indicated by the arrow on the front or rear template. The arrow should have the word “UP” next to the arrow. The arrow and the text are yellow with a height of 50 mm.
14. There should be no pits, rust, excess rings, water vapor, oil holes, etc. on the surface of the formwork and defects that affect the appearance.
15. The mold should be easy to hoist and transport. 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.
Second, mold material and hardness
1. The mold formwork should be a standard formwork that conforms to the standard.
2. Molded parts and casting systems (cores, moving mold inserts, movable inserts, split cones, push rods, sprue sleeves) are made of materials with properties 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 surfaces should be protected against corrosion.
4. The hardness of the molded parts of the mold should be no less than 50HRC, or the hardness of the surface hardening treatment should be higher than 600HV.
Third, ejector, reset, thrust ferrule, take-up
1. It should be smooth, no stuck, and no abnormal sound when it is ejected.
2. The sloping top surface should be polished and the sloping top surface is lower than the core surface.
3. The sliding part should be filled with oil groove, the surface should be nitrided, and the surface hardness after treatment is HV700 or above.
4. All rams should have a non-rotation position and each ram should be numbered.
5. Ejection distance is limited by the application limit block
6. The return spring should be made of standard parts, and the ends of the spring should not be ground or cut.
7. The slider and core should have the travel limit. The small slider is limited by the 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 inclined column, and the angle of the inclined guide column should be 2°~3° smaller than the angle of the slider locking surface. If the stroke of the slider is too long, the cylinder should be drawn.
9. When the end face of the cylinder core forming part is covered, the cylinder should be self-locking mechanism.
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 pins should not be strung up and down.
12. Add barbs to the ejector pin. The direction of the barbs should be the same. The barbs are easy to remove from the product.
13. The matching clearance between the jack hole and the ejector pin, the length of the sealing section, and the surface roughness of the ejector hole shall be in accordance with the relevant enterprise standards.
14. The product should be suitable for the operator to remove.
15. When the product is ejected, it is easy to follow the inclined top. The ejector pin should be grooved or etched.
16. The top block fixed on the ram should be firm and reliable. The non-formed part should be machined to a slope of 3°~5°, and the lower part should be chamfered.
17. There should be no iron filings in the oil passage holes on the formwork.
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 installation 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. There must be no clearance for the locating pin installation.
Fourth, cooling, heating system
1. The cooling or heating system should be fully ventilated.
2. The seal should be reliable. The system should not leak under the pressure of 0.5MPa, and it is easy to overhaul.
3. The size and shape of the sealing groove on the formwork shall comply with the relevant standards.
4. When the sealing ring is placed, it should be spread with butter and placed higher than the mold surface.
5. Water and oil passage spacers should be made of materials that are not susceptible to corrosion.
6. The front and rear molds should adopt centralized water supply and mode.
Five, pouring system
1. The gate setting should not affect the appearance of the product and meet the product assembly.
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. At the same time, the plastics lost in the casting system should be the least.
3. The partial section of the three-plate mold runner on the back 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 entrance should be less than 3 mm. The ball head has a 3 mm deep stepped recessed gate plate.
5. The ball pull rod should be securely fixed and can be pressed under the positioning ring. It can be fixed with headless screws or pressed with a pressure plate.
6. Gates and runners should be machined according to the size requirements of the drawings, and manual grinders are not allowed to be processed.
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 pull rod should have a smooth transition.
10. The splitter on the parting surface should be round and the front and rear modes should not be misaligned.
11. The latent gate on the ejector pin should have no surface shrinkage.
12. The diameter and depth of the cold hole of the transparent product should meet the design standards.
13. The material is easy to remove, the appearance of the product has no gate marks, and there is no residual material in the assembly of the product.
14. Bent hooking the gate, the two parts of the block should be nitrided, the surface hardness reaches HV700.
Sixth, hot runner system
1. The hot runner wiring layout should be reasonable and easy to overhaul. The wiring numbers should correspond one-to-one.
2. The hot runner should be tested for safety and the insulation resistance to ground is greater than 2MW.
3. Temperature control cabinet and hot nozzle, hot runner should use standard parts.
4. The main flow sleeve is connected with the hot runner by the thread, and the bottom surface is in contact with the seal.
5. The hot runner is in good contact with the heating plate or the heating rod. The heating plate is fixed by screws or studs and the surface is well fitted.
6. A type J thermocouple should be used and matched to the temperature control meter.
7. Each set of heating elements should have thermocouple control and the thermocouple position should be properly arranged.
8. The nozzle should meet the design requirements.
9. The hot runner should be reliably positioned, with at least two locating pins or screws.
10. There should be a thermal insulation pad between the hot runner and the template.
11. The temperature difference between the temperature setting table and the actual display temperature should be less than ±5 °C, and the temperature control is sensitive.
12. The cavity and nozzle mounting holes should be punched through.
13. The hot runner wiring should be bundled and covered with a pressure plate.
14. There are two sockets of the same size and should be clearly marked.
15. The control line should be jacketed and undamaged.
16. The temperature control cabinet has a reliable structure and the screws are not loose.
17. The socket is mounted on a bakelite and cannot exceed the size of the template.
18. Wires should not be exposed outside the mold.
19. All hot runners or stencils should have rounded corners where they come into contact with the wires.
20. There is no open circuit short circuit on all lines before the template is assembled.
21. All wiring should be properly connected and the insulation performance is good.
22. After clamping the template, all lines are checked again with a multimeter.
Seven, molding part, parting surface, exhaust groove
1. There should be no defects such as unevenness, pits, rust and other appearances on the front and back mold surfaces.
2. The insert is matched with the mold frame, and the rounded corners should have a gap of less than 1 mm.
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. The insert research and development should be in place, and the placement is smooth and the positioning is reliable.
6. Inserts, inserts, etc. should be securely positioned and fixed, the round pieces are stopped, and the copper and iron pieces are not placed under the inserts.
7. The end of the ejector pin is consistent with the core.
8. There are no defects such as undercut and chamfer in the front and rear molded parts.
9. The ribs should go out smoothly.
10. Multi-cavity mold products, the left and right parts are symmetrical, should be marked L or R. If the customer has requirements on the position and size, it should meet the customer's requirements, generally added in the place that does not affect the appearance and assembly, 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 ram 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 sealant part should meet the design standards. 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 meet customer requirements evenly.
17. For products with the required appearance, the screws on the product shall be protected against shrinkage.
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 deviation should be controlled below ±0.15 mm.
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 be securely fixed.
22. The front mold is inserted into the front mold or the rear mold is inserted into the front mold. The surrounding mold should be locked with a bevel and machined to avoid air.
Eight, 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 generally be less than 85% of the injection pressure of the injection molding machine.
3. The injection speed of the mold injection molding production, the injection speed of three quarters of the stroke is not less than 10% of the rated injection speed or more than 90% of the rated injection speed.
4. The holding pressure during mold injection production should generally be less than 85% of the actual injection pressure.
5. The clamping force during mold injection production should be less than 90% of the rated clamping force of the applicable model.
6. During the injection molding process, the removal of the product and the nozzle material should be easy and safe (the time is generally less than 2 seconds).
7. Molds with inserts are easy to install and secure for inserts during production.
Nine, packaging, transportation
1. The mold cavity should be cleaned and sprayed with anti-rust oil.
2. The sliding parts should be lubricated.
3. Apply grease to the sprue feed inlet.
4. The mold should be fitted with a locking die, and the specifications meet the design requirements.
5. Spare parts for spare parts should be complete with a list and supplier name.
6. The water, liquid, gas and electricity inlet and outlet of the mold should be sealed to prevent foreign matter from entering.
7. The outer surface of the mold is sprayed with paint, and the customer has the required requirements.
8. The mold should be moisture-proof, waterproof, and prevent bumper packaging, as required by the customer.
9. Mold product drawings, structural drawings, cooling and heating system drawings, hot runner drawings, spare parts and mold material supplier details, instructions for use, test mode report, factory inspection certificate, electronic documents should be complete.
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