Injection Mold Acceptance Standard

To ensure that the injection mold can produce qualified products, put into production normally, ensure the mold production life and meet the production use requirements of product design. To regulate the criteria for approving molds in terms of product quality, mold structure, and injection molding process requirements, whereby the quality of molds is evaluated.

Reference standard.
GB/T12554-2006 plastic injection mold technical conditions
GB/T4169.1~4169.23-2006 injection mold parts
GB/T12556-2006 plastic injection mold mold frame technical conditions
GB/T14486-2008 Dimensional tolerances for plastic molded parts

1）、Appearance, size and fit of molded products

1、No defects are allowed on the product surface: missing material, burnt, top white, white lines, phi peaks, blistering, pulling white (or pulling crack, pulling off), baking marks, wrinkles.

2、fusion marks: general round perforation fusion mark length is not more than 5mm, shaped perforation fusion mark length is less than 15mm, fusion mark strength and can pass the functional safety test.

3、Shrinkage: no shrinkage is allowed on the obvious part of the appearance surface, and slight shrinkage is allowed on the inconspicuous part (no dent in the hand).

Variants: general small product plane unevenness is less than 0.3mm, there are assembly requirements need to ensure the assembly requirements.

4、The appearance of obvious places can not have air lines, material flowers, the product generally can not have air bubbles.

5、The geometry, size and accuracy of the product shall conform to the requirements of the officially valid mold opening drawings (or 3D files), and the product tolerance shall be according to the tolerance principle, with negative tolerance for shaft size and positive tolerance for hole size, as required by the customer.

6、product wall thickness: product wall thickness is generally required to achieve the average wall thickness, non-average wall thickness should be in line with the requirements of the drawings, tolerance should be achieved according to the characteristics of the mold -0.1mm.

7、Product fit: surface shell bottom shell fit: surface misalignment less than 0.1mm, no scratching, with the requirements of the hole, shaft, surface to ensure that the fit interval and use requirements.

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

2、The nameplate should be fixed on the mold foot near the template and the reference corner. The nameplate should be fixed reliably and not easy to peel off.

3、Cooling water nozzle should be selected with plastic block insert nozzle, the customer otherwise required according to the requirements.

4、The cooling water nozzle should not protrude from the surface of the mold frame.

5、Cooling water nozzle need to process the countersink hole, countersink hole diameter of 25mm, 30mm, 35mm three specifications, hole chamfering, chamfering should be consistent.

6、cooling water nozzle should be marked in and out.

7、Marking English characters and numbers should be greater than 5/6, positioned 10mm directly below the spout, the handwriting should be clear, beautiful, neat and evenly spaced.

8、Mold accessories should not affect the lifting and storage of the mold. There are exposed cylinders, water nozzles, pre-set mechanism, etc. below the installation, which should be protected by supporting legs.

9、The installation of the support leg should be fixed on the mold frame with screws through the support leg, and the long support leg can be fastened to the mold frame by turning the external thread post.

10、The size of the ejector hole of the mold should meet the requirements of the specified injection molding machine, except for small molds, which cannot be ejected with only one center.

11、The positioning ring should be fixed reliably, the diameter of the ring is 100mm, 250mm, the positioning ring is 10~20mm higher than the base plate, except if the customer requires otherwise.

12、The mold outline size should meet the requirements of the specified injection molding machine.

13、The installation direction of the mold should be marked with arrows on the front or rear template, and the word “UP” should be next to the arrow, the arrow and the text are yellow, and the height of the word is 50mm.

14、The surface of the mold frame should not have pits, rust stains, extra rings, in and out of water vapor, oil holes, etc. and defects affecting the appearance.

15、The mold should be easy to lift and transport, and the mold parts should not be disassembled when lifting, and the lifting ring should not interfere with the spigot, cylinder, pre-set lever, etc.

3）、mold material and hardness

1、The mold frame should be chosen to meet the standard mold frame.

2、Mould forming parts and pouring system (core, movable and fixed mold insert, movable insert, manifold cone, push rod, gate sleeve) are made of materials with higher performance than 40Cr.

3、molding to mold corrosion-prone plastics, molding parts should be made of corrosion-resistant materials, or its molding surface should take anti-corrosion measures.

4、The hardness of molded parts should be not less than 50 HRC or the surface hardening treatment should be higher than 600 HV.

4）、eject, reset, draw core, take parts

1、The ejection should be smooth, no jamming, no abnormal sound.

2、The slant top surface should be polished and the slant top surface should be lower than the core surface.

3、The sliding parts should be opened with oil grooves, and the surface should be nitride treated, and the surface hardness should be HV700 or above after treatment.

4、All top bars should have stop rotation positioning, and each top bar should be numbered.

5、The ejection distance should be limited by the limit block.

6、The reset spring should be selected as a standard part, and the ends of the spring should not be polished and cut off.

7、slider, extractor should have travel limit, small slider with spring limit, spring inconvenient installation can be used when the bob screw; cylinder extractor must have a travel switch.

8、Slider core extraction generally uses the oblique guide column, the angle of the oblique guide column should be smaller than the angle of the slider locking surface 2 ° ~ 3 °. The slider stroke is too long should be used for cylinder extraction.

9、When the end face of the core forming part of the cylinder is wrapped, the cylinder should add a self-locking mechanism.

10、Slider width of more than 150mm below the large slider should be wear-resistant plate, wear-resistant plate material should be selected T8A, after heat treatment hardness of HRC50 ~ 55, wear-resistant plate than the large surface higher than 0.05 ~ 0.1mm, and open the oil groove.

11、The top bar should not move up and down in series.

12、Add barbs on the top bar, the direction of the barbs should be consistent, and the barbs are easy to remove from the product.

13、The clearance between the top rod hole and the top rod, the length of the sealant section, and the surface roughness of the top rod hole should be in accordance with the requirements of relevant enterprise standards.

14、The product should be conducive to the operator to remove.

15、The product is easy to follow the slanting top when ejected, the top bar should be grooved or etched.

16、Fixed in the top bar on the top block, should be solid and reliable, around the non-forming part should be processed 3 ° ~ 5 ° slope, the lower periphery should be chamfered.

17、The oil circuit holes on the mold frame should be free of iron filings and debris.

18、Flat end face of return rod, no spot welding. No gasket at the bottom of the embryo head, spot welded.

19、The three-plate mold gate plate guide slides smoothly and the gate plate is easy to pull apart.

20、Three plate mold limit tie should be arranged on both sides of the mold installation direction, or in the mold frame plus the tie plate to prevent the limit tie from interfering with the operator.

21、The oil and gas channels should be smooth, and the hydraulic ejector reset should be in place.

22、The bottom of the guide sleeve should be opened to make the exhaust port.

23、The locating pin must not be installed with clearance.

5）、Cooling and heating system

1、The cooling or heating system should be sufficiently unobstructed.

2、The seal should be reliable, and the system should not leak under 0.5MPa pressure and be easy to repair.

3、The size and shape of the sealing groove opened on the mold frame should meet the requirements of relevant standards.

4、The seal should be greased when it is placed and placed above the surface of the mold frame.

5、Water and oil runner spacer should be made of materials that are not susceptible to corrosion.

6、The front and back of the mold should be used to centralize the water supply, the way.

6）、Pouring system

1、The gate setting should not affect the product appearance and meet the product assembly.

2、The cross-section and length of the flow channel should be designed reasonably to shorten the flow as much as possible under the premise of ensuring the quality of forming, reduce the cross-sectional area to shorten the filling and cooling time, and at the same time, the plastic lost in the pouring system should be the least.

3、The cross section of the part of the three-slab mold sprue at the back of the front formwork should be trapezoidal or semi-circular.

4、The three-plate mold has a material break on the sprue plate, the sprue entrance diameter should be less than 3mm, and there is a 3mm deep step recessed into the sprue plate at the ball head.

5、The ball pulling rod should be fixed reliably, it can be pressed under the positioning ring, fixed with headless screws or pressed with a pressure plate.

6、The sprue and runner should be processed by machine according to the drawing size requirements, not allowed to hand shake grinding machine processing.

7、The point sprue gate should be in accordance with the specification.

8、The front of the manifold should have an extended section as a cold cavity.

9、The Z-shaped inverted buckle of the pulling rod should have a smooth transition.

10、The manifold on the parting surface should be round, and the front and rear mold should not be misaligned.

11、The submerged sprue on the top bar should be free of surface shrinkage.

12、The diameter and depth of the cold material cavity of transparent products should be in accordance with the design standards.

13、The material handle is easy to remove, the appearance of the product is free of gate marks, and there is no residual material handle at the product assembly.

14、Curved hook submerged sprue, two parts of inserts should be nitrided and the surface hardness should reach HV700.

7）Hot runner system

1、Hot runner wiring layout should be reasonable, easy to access, wiring number should correspond one by one.

2、The hot runner should be tested for safety, with insulation resistance to ground greater than 2MW.

3、Temperature control cabinet and hot nozzle, hot runner should be standard parts.

4、The main flow port sleeve is connected to the hot runner with threads and the bottom surface flat contact seal.

5、The hot runner is in good contact with the heating plate or heating rod, the heating plate is fixed with screws or studs, and the surface is well laminated.

6、J-type thermocouple should be used and matched with the temperature control meter.

7、Each group of heating elements should have thermocouple control, thermocouple position is reasonably arranged.

8、Nozzle should meet the design requirements.

9、The hot runner should be reliably positioned, with at least two positioning pins, or fixed with screws.

10、There should be heat insulation pads between the hot runner and the template.

11、Temperature control table set temperature and the actual display temperature error should be less than ± 5 ° C, and sensitive temperature control.

12、The cavity and nozzle mounting holes should be penetrated.

13、Hot runner wiring should be bundled and covered with a pressure plate.

14、There are two sockets of the same size, which should be clearly marked.

15、The control line should be sheathed and undamaged.

16、Temperature control cabinet has reliable structure and no loose screws.

17、The socket is installed on the Bakelite and cannot exceed the maximum size of the template.

18、The electric wire should not be exposed outside the mold.

19、Hot runner or template all contact with the wire should be rounded corner transition.

20、All wiring is free of breaks and shorts before the template is assembled.

21、All wiring should be properly connected and well insulated.

22、After the template is mounted and clamped, all lines should be checked again with a multimeter.

8)、forming part, parting surface, exhaust slot

1、The surface of the front and rear mold should not have unevenness, pits, rust and other defects affecting the appearance.

2、The inlay and the mold frame should have a clearance of less than 1mm around the rounded corners.

3、The fractal surface is kept clean, neat, no portable grinding wheel to avoid empty, and no dent in the sealant part.

4、The depth of the exhaust slot should be less than the overflow edge value of the plastic.

5、The insert should be in place, smoothly placed and reliably positioned.

6、Inserts, inserts, etc. should be reliably positioned and fixed, round pieces with stop rotation, no copper or iron pads under the inserts.

7、The end face of the top bar is in line with the core.

8、No defects such as inverted buckle and chamfer in the molding part of the front and rear mold.

9、The bar position should be ejected smoothly.

10、multi-cavity mold products, left and right pieces symmetrical, should indicate L or R, customer requirements for location and size, should be in line with customer requirements, generally in the place that does not affect the appearance and assembly added, the font size of 1/8.

11、mold frame locking surface research and matching should be in place, more than 75% of the area encountered.

12、The top bar should be arranged closer to the side wall and next to the tendons and tabs, and use larger top bars.

13、For the same piece should indicate the number 1, 2, 3, etc.

14、Each touch through surface, insert through surface, parting surface should be in place.

15、The sealing glue part of the parting surface should conform to the design standard. 10~20mm for medium-sized moulds and below, 30~50mm for large moulds, and the rest of the part is machined to avoid hollow.

16、The skin pattern and sandblasting should be uniform to meet customer requirements.

17、appearance requirements of the products, the products on the screws should be anti-shrinkage measures.

18、Screw columns with a depth of more than 20mm should be selected as top pipes.

19、The wall thickness of the products should be uniform, and the deviation should be controlled below ±0.15mm.

20、The width of the reinforcement should be less than sixty percent of the wall thickness of the exterior surface.

21、The inserted core on the slanting top and slider should be fixed in a reliable way.

22、The front mold inserted into the back mold or the back mold inserted into the front mold, there should be bevel locking around and machined to avoid hollow.

9）、injection molding production process

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

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

3、The injection speed of the mold during injection production is not less than 10% of the rated maximum injection speed or more than 90% of the rated maximum injection speed for three quarters of the stroke.

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

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

6、During the injection molding process, the product and the spout material should be removed easily and safely (the time is generally not more than 2 seconds each).

7、Moulds with inserts for products, easy installation of inserts and reliable fixing of inserts during production.

10）、packaging, transportation

1、The mold cavity should be cleaned and sprayed with anti-rust oil.

2、Sliding parts should be lubricated.

3、The gate sleeve inlet port should be sealed with grease.

4、The mold should be installed with the clamping piece and the specifications should be in accordance with the design requirements.

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

6、mold water, liquid, gas, electricity import and export should take sealing measures to prevent the entry of foreign objects.

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

8、The packaging should be moisture-proof, water-proof and bump-proof, as required by the customer.

9、Mould product drawings, structural drawings, cooling and heating system drawings, hot runner drawings, spare parts and mold material supplier details, instruction manuals, mold test reports, factory test certificates, electronic files should be complete.

11）、Acceptance determination

1、The mold should be checked and accepted according to the requirements of this standard article by article, and make acceptance records.

2、Acceptance determination is divided into qualified items, acceptable items and unacceptable items, all items are qualified or acceptable items, the mold is qualified.

3、Unacceptable items: 1 item of product; 1 item of mold material; 4 items of mold appearance; 2 items of ejector reset extraction core; 1 item of cooling system; 2 items of pouring system; 3 items of hot runner system; 3 items of molding part; 1 item of production process; 3 items of packaging and transportation; then it is judged that the mold needs to be rectified.

4、Unacceptable items: product more than 1 item; mold material more than 1 item; mold appearance more than 4 items; ejection reset extraction core more than 2 items; cooling system more than 1 item; pouring system more than 2 items; hot runner system more than 3 items; molding part more than 3 items; production process more than 1 item; packaging and transportation more than 3 items; then judged as unqualified mold

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