109 acceptance criteria for molding

Time:2020-04-25 08:58:41 / Popularity: / Source:

After molding is completed, it needs to be accepted as a purchaser. How to inspect a pair of manufactured molds? What are inspection standards? China mold factory Gud Mould Industry Limited believes that mold inspection mainly include mold structure design, appearance, structural parts, mold parts processing precision, inlaying method, materials, heat treatment methods, and so on.
molded products 

First, appearance, size and cooperation of molded products

1. Surface of molded products is not allowed to be defective: lack of material, burnt, white, peak, foaming, whitening (or cracking, breaking), baking, wrinkles.
2. Weld marks: Generally, length of circular perforated weld line is not more than 5mm, length of shaped perforated weld line is less than 15mm, and weld line strength can pass functional safety test.
3, Shrinkage: Appearance of surface is not allowed to shrink, inconspicuous places allow for slight shrinkage (no dents).
4, General small product flatness is less than 0.3mm, there are assembly requirements to ensure assembly requirements.
5, Place with obvious appearance can not have gas lines, flurs, products generally can not have bubbles.
6, Product geometry, size and accuracy should meet requirements of formal and effective mold opening drawings (or 3D documents), product tolerances should be based on tolerance principles, shaft dimensional tolerances are negative tolerances, hole size tolerances are positive tolerances, Produce if special requirement from customers.
7. Product wall thickness: Wall thickness of product generally requires average wall thickness. Non-average wall thickness should meet requirements of drawings. Tolerance should be -0.1mm according to mold characteristics.
8. Product matching: Face shell is matched with bottom case - surface misalignment is less than 0.1mm, there is no shaving phenomenon, and holes, shafts and faces with matching requirements should be guaranteed to meet spacing and use requirements.

Second, appearance of molding

1. Mold nameplate is complete in content, clear in characters and neatly arranged.
2. Nameplate should be fixed on mold foot near template and reference angle. Nameplate is fixed and not easy to peel off.
3, Cooling nozzle should use plastic block water nozzle, specialized if requirements from customer.
4. Cooling nozzle should not protrude from surface of mold base.
5, Cooling nozzle needs to process countersunk holes, diameter of counterbore is 25mm, 30mm, 35mm three kinds of specifications, chamfer of holes should be consistent.
6. Cooling nozzle should have an ingress and exit mark.
7. Mark English characters and numbers should be greater than 5.
8. Position is 10mm below water nozzle. Writing should be clear, beautiful, neat and evenly spaced.
9, Mold parts should not affect lifting and storage of molding. There should be exposed cylinders, faucets, pre-reset mechanisms under installation, and should have support leg for protection.
10. Mounting legs of supporting legs are fixed on formwork through supporting legs, and too long supporting legs can be fastened to formwork by external threaded columns.
11. Size of die ejection hole should meet requirements of specified injection molding machine. Except for small mold, it cannot be used only with one center.
12. Positioning ring should be fixed and reliable. Diameter of ring is 100mm and 250mm. Positioning ring is 10~20mm above bottom plate. Except other requirement from customers.
13, Molding dimensions should meet requirements of specified injection molding machine.
14. Molding with required direction should be marked with arrow on front or rear template. There should be “UP” next to arrow. Arrow and text are yellow and height is 50mm.
15. Surface of formwork should not have pits, rust, excess rings, water vapor, oil holes as well as defects affecting appearance.
16. Molding should be easy to hoist and transport. When hoisting, mold parts must not be disassembled. Lifting ring must not interfere with water nozzle, oil cylinder and pre-reset rod.

Third, mold material and hardness

1. Mold formwork should be a standard formwork that conforms to standard.
2, Mold parts and casting system (core, moving mold inserts, movable inserts, split cones, push rods, sprue sleeves) materials use materials with properties higher than 40Cr.
3. When molding plastics that are corrosive to mold, mold parts should be made of corrosion-resistant materials, or molding surface should be protected against corrosion.
4. Hardness of mold parts of mold should not be lower than 50HRC, or hardness of surface hardening treatment should be higher than 600HV.
molding 

Fourth,demoulding, reset, thrust ferrule, take-up

1. It should be smooth, no stuck, and no abnormal sound when it is ejected.
2. Inclined top surface should be polished, and inclined top surface is lower than core surface.
3. Sliding part should be filled with oil groove, and surface should be nitrided. Surface hardness after treatment is HV700 or above.
4. All ejector pins should have anti-rotation positioning, and each ejector pin should be numbered.
5. Ejector distance is applied to limit block for limiting.
6, Return spring should use standard parts, spring ends must not be polished, cut.
7. Slider and core should have travel limit. Small slider is limited by spring. When spring is inconvenient to install, wave screw can be used. Cylinder core must have a travel switch.
8. Slider core is generally inclined, and angle of inclined guide column should be 2°-3° smaller than angle of slider locking surface. If stroke of slider is too long, cylinder should be drawn.
9. When end face of cylinder core forming part is covered, cylinder should be self-locking mechanism.
10. Large slider with a slider width exceeding 150mm should have a wear plate underneath. Wear plate material should be T8A. After heat treatment, hardness is HRC50-55. Wear plate is 0.05-0.1mm higher than large surface and oil tank is opened.
11, Ejector should not be strung up and down.
12. Add barbs to ejector pin. Direction of barbs should be consistent. Barbs are easy to remove from product.
13. Matching clearance between jack hole and ejector pin, length of sealing section, and surface roughness of ejector hole shall be in accordance with relevant enterprise standards.
14. Product should be suitable for operator to take it off.
15. When product is ejected, it is easy to follow oblique top. Ejector pin should be grooved or etched.
16. Top block fixed on ram should be firm and reliable. Non-formed part should be processed by 3°-5°, and lower part should be chamfered.
17. There should be no iron filings in oil passage hole on mold base.
18, Return rod end face is flat, no spot welding. There is no gasket at the bottom of embryo, spot welding.
19. Three-plate mold gate plate slides smoothly, and gate plate is easy to pull open.
20. Three-plate mold limit rod should be placed on both sides of mold installation direction, or pull plate should be added outside mold frame to prevent limit rod from interfering with operator.
21, Oil passage airway should be smooth, hydraulic ejection reset should be in place.
22. Exhaust port should be opened at the bottom of guide sleeve.
23. There should be no clearance for positioning pin installation.

Five, cooling, heating system

1. Cooling or heating system should be fully ventilated.
2, Seal should be reliable, system should not have leakage under pressure of 0.5MPa, easy to overhaul.
3. Size and shape of sealing groove opened on formwork shall comply with relevant standards.
4. When sealing ring is placed, it should be buttered and placed higher than mold surface.
5. Water and oil flow passage spacers should be made of materials that are not susceptible to corrosion.
6. Front and rear molds should adopt centralized water supply method.

Sixth, gating system

1. Gate setting should not affect appearance of product and meet product assembly.
2. Cross-section and length of runner should be designed reasonably. Process should be shortened as much as possible under premise of ensuring forming quality, and cross-sectional area should be reduced to shorten filling and cooling time. While casting system should lose the least amount of plastic.
3. Partial section of three-plate mold runner on the back of front template shall be trapezoidal or semi-circular.
4. Three-plate mold has a material-breaking plate on gate plate. As adviced from China mold factory Gud Mould Industry Limited, diameter of runner inlet should be less than 3 mm, and ball head has a deep 3 mm step of recessed gate plate.
5, Ball pull rod should be securely fixed, can be pressed under positioning ring and fixed with headless screws, or can be pressed with a pressure plate.
6, Gates, runners should be machined according to size requirements of drawings, not allowed manual grinding machine processing.
7. Point gate should be in accordance with specifications.
8. Front end of runner should have an extension as a cold pocket.
9. Z-shaped inverted buckle of pulling rod should have a smooth transition.
10. Splitter on parting surface should be round, front and rear modes should not be misaligned.
11. Latent gate on ejector rod should have no surface shrinkage.
12. Diameter and depth of cold hole of transparent products should meet design standards.
13. Material is easy to remove, appearance of product has no gate marks, and there is no residual material in assembly of product.
14, Bent hook latent gate, two parts of block should be nitrided, surface hardness of HV700.
mold parts 

Seven, forming part, parting surface, exhaust groove

1. There should be no defects such as unevenness, pits, rust and other effects on the surface of front and rear molds.
2. Insert is matched with mold frame, and rounded corners should have a gap of less than 1mm.
3. Parting surface is kept clean and tidy, and there is no portable grinding wheel to avoid air, and sealing part has no depression.
4. Depth of exhaust groove should be less than overflow value of plastic.
5, Insert research and development should be in place, placement is smooth, and positioning is reliable.
6, Inserts should be reliably positioned and fixed, circular pieces have a rotation, bottom of block is not padded with copper, iron.
7. End face of ejector pin is consistent with core.
8. There are no defects such as undercut and chamfer in front and rear mold forming parts.
9. Ribs should be released smoothly.
10, Multi-cavity molded products, left and right parts are symmetrical, should be marked L or R. If customers have requirements on location and size, it should meet customer’s requirements, generally added to place where appearance and assembly are not affected, font size is 1/8.
11, Mold frame locking surface research and distribution should be in place, more than 75% of  area encountered.
12. Ejector rod should be placed close to side wall, beside ribs and bosses, and use a larger ram.
13. For same piece, numbers 1, 2, 3, etc. should be noted.
14. Each touch surface, insert surface, and parting surface should be in place.
15. Parting surface sealing part should meet design standards. Medium-sized mold is 10-20mm, large mold is 30-50mm, and rest is machined to avoid air.
16. Skin and sandblasting should meet customer requirements evenly.
17, Appearance of required products, screws on product should have anti-shrinkage measures.
18. Top of screw column with a depth of more than 20mm should be used.
19. Wall thickness of product should be uniform and deviation should be controlled below ±0.15mm.
20, Width of ribs should be less than 60% of wall thickness of appearance.
21. Core of inclined top and slider should have a reliable fixing method.
22. Front mold is inserted into front mold or rear mold is inserted into front mold. Surrounding mold should be locked with a bevel and machined to avoid air.

Eight, injection molding production process

1. Mold should have stability of injection molding production and repeatability of process parameter adjustment within range of normal injection molding process conditions.
2. Injection pressure during mold injection production should generally be less than 85% of maximum injection pressure of injection molding machine.
3. Injection speed of mold injection molding production, injection speed of three-quarter stroke is not less than 10% of rated maximum injection speed or more than 90% of rated maximum injection speed.
4. Holding pressure during mold injection production should generally be less than 85% of actual maximum injection pressure.
5. Clamping force during mold injection production should be less than 90% of rated clamping force of applicable model.
6. In process of injection molding, removal of products and nozzles should be easy and safe ( time is generally less than 2 seconds).
7. Molding with insert products is easy to install and secure when insert is fixed during production.

Nine, packaging, transportation

1. Mold cavity should be cleaned and sprayed with anti-rust oil.
2. Sliding parts should be coated with lubricating oil.
3. Gate of sprue bushing should be sealed with grease.
4, Molding should be installed with a locking die, specifications meet design requirements.
5, Spare parts wearing parts should be complete, with a list of suppliers and name of supplier.
6. Inlet and outlet of mold water, liquid, gas and electricity shall be sealed to prevent foreign matter from entering.
7. Outer surface of molding is sprayed with paint, and produce if special requirement from customers.
8, Molding should be moisture-proof, waterproof to prevent bumper packaging, produce if special requirement from customers.
9, China mold factory Gud Mould Industry Limited suggest, mold product drawings, structural drawings, cooling heating system drawings, hot runner drawings, spare parts and mold materials supplier details, instructions for use, test mode report, factory inspection certificate, electronic documents should be complete.

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