Note: The injection mold acceptance must be done at 10 points.

Pay attention to the following problems in the acceptance of injection molds
First, the appearance, size and cooperation of the molded product
1. The surface of the product is not allowed to be defective: lack of material, burnt, white, white, peak, foaming, whitening (or cracking, breaking), baking, wrinkles. .
2. Weld marks: Generally, the length of the circular perforated weld line is not more than 5 mm, the length of the shaped perforated weld line is less than 15 mm, and the weld line strength can pass the functional safety test. .
3. Shrinkage: The appearance of the surface is not allowed to shrink, and it is not obvious that it is slightly shrunk (the hand does not have a dent).
4. Generally, the flatness of small products is less than 0.3mm, and there are assembly requirements to ensure assembly requirements.
5. Appearance is obvious that there should be no air grain or material flower, and the product generally cannot have air bubbles. .
6. The geometric shape and dimensional accuracy of the product shall conform to the requirements of the formal and effective mold opening drawing (or 3D file). The tolerance of the product shall be based on the tolerance principle, the tolerance of the shaft type shall be the negative tolerance, and the tolerance of the dimensional dimension of the hole shall be the positive tolerance. Required as required. .
7. Product wall thickness: The product wall thickness generally requires the average wall thickness. The non-average wall thickness should meet the requirements of the drawings. The tolerance should be -0.1mm according to the mold characteristics. .
8. Product matching: the bottom shell of the shell is matched: the surface misalignment is less than 0.1mm, there is no shaving phenomenon, and the holes, shafts and surfaces with matching requirements should ensure the matching interval and use requirements.
Second, 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 from the surface of the mold base
5. The cooling nozzle needs to process the counterbore. The diameter of the counterbore is 25mm, 30mm and 35mm. The chamfering of the hole should be consistent. .
6. The cooling nozzle should have an ingress and exit mark.
7. Mark English characters and numbers should be greater than 5/6, the position is 10mm directly below the water nozzle, and 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. The mounting legs of the support legs 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 ejection 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 mold dimensions should meet 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 and the height is 50mm.
14. The surface of the mold frame should not have pits, rust, excess rings, water vapor, oil holes, etc., as well as defects affecting the appearance.
15. The mold should be easy to hoist and transport, and the mold parts should not be disassembled during lifting. The lifting ring must not interfere with the water nozzle, oil cylinder and pre-reset rod.
Third, mold material and hardness
1. The mold formwork should use 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 forming 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 part of the mold should not be lower than 50HRC, or the hardness of the surface hardening treatment should be higher than 600HV.
Fourth, ejector, reset, thrust ferrule, take-up
1. It should be smooth, no stuck, and no abnormal sound when it is ejected.
2. The inclined top surface should be polished, and the inclined 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 ejector pins should have a non-rotation position, and each ram should be numbered.
5. The ejector distance is applied to the limit block for limiting.
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 the core should have the travel limit. The small slider is limited by the spring. When the spring is inconvenient to install, the wave screw can be used. The cylinder core must have a travel switch.
8. The slider core is generally inclined column, 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. The slider with a width of more than 150mm should have a wear plate underneath. The material of the wear plate should be T8A. After heat treatment, the hardness is HRC50~55. The wear plate is 0.05~0.1mm higher than the large face. 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 consistent. The barbs are easy to remove from the product.
13. The matching clearance between the ejector 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 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 ram should be firm and reliable. 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 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 should be no clearance for the positioning pin installation.
Five, 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 opened on the formwork shall comply with the relevant standards.
4. When the sealing ring is placed, it should be buttered 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.
Sixth, the 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, and the ball head has a step of 3 mm deep recessed into the gate plate.
5. The ball pull rod should be fixed reliably, can be pressed under the positioning ring, can be fixed with headless screws, or can be pressed with pressure plate.
6. The gate and runner should be machined according to the size requirements of the drawings, and manual grinder grinding is not allowed.
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 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 rod 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.
Seven, hot runner system
1. The hot runner wiring layout should be reasonable, easy to overhaul, and 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 mainstream mouthpiece 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, and 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 group of heating elements should be controlled by thermocouples, and the position of the thermocouples is reasonable.
8. The nozzle should meet the design requirements.
9. The hot runner should be reliably positioned, 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 control table setting temperature and the actual display temperature error 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 sheathed without damage.
16. The temperature control cabinet has a reliable structure and the screws are not loose.
17. The socket is mounted on the bakelite and cannot exceed the maximum 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 the template is clamped, all lines are checked again with a multimeter.
Eight, molding part, parting surface, exhaust slot
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 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. 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 reliably positioned and fixed, the round pieces have a rotation stop, and the copper pieces 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 be released smoothly.
10. Multi-cavity mold products, the left and right parts are symmetrical, should be marked L or R, customers have requirements on the location and size, should meet customer requirements, generally 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 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 researched and placed in place.
15. The parting surface sealing 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. The product with the required appearance, the screws on the product shall have anti-shrinkage measures.
18. The top of the screw column with a depth of more than 20mm should be used.
19. The wall thickness of the product should be uniform and the deviation 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 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.
Nine, injection molding production process
1. The mold should have the stability of injection molding production and the repeatability of process parameter adjustment within the range of normal injection molding process conditions.
2. The injection pressure during mold injection production should generally be less than 85% of the maximum injection pressure of the injection molding machine.
3. The injection speed during mold injection production, the injection speed of three quarters of the stroke is not less than 10% of the rated maximum injection speed or more than 90% of the rated maximum injection speed.
4. The holding pressure during mold injection production should generally be less than 85% of the actual maximum 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. In the injection molding process, the removal of the product and the nozzle material should be easy and safe (the time generally does not exceed 2 seconds).
7. The mold with insert products is easy to install and secure for inserts during production.
Ten, packaging, transportation
1. The mold cavity should be cleaned and sprayed with anti-rust oil.
2. The sliding parts should be lubricated.
3. The gate of the sprue bushing should be sealed with grease.
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 inlet and outlet of mold water, liquid, gas and electricity shall 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.

Pyrite as Fillers Used in Grinding Wheels/ Abrasive Tools

Ablation grinding wheel / abrasive( filling agent )

PYRITE__As fillers used in grinding wheels/ abrasive tools


Place of Origin: Henan Luoyang, China

Pyrite, Iron pyrites, pyrites lump, Ferro sulphur, Pyrites powder.

Product Description

Detailed introduction:  is filling agent for ablating grinding wheel abrasive, which can effectively reduce the grinding wheel temperature during ablation, improve the heat resistance, and prolong the service life of the grinding wheel.

Formation of a protective layer 
(1)The reaction absorbing oxygen occurs between 400 and 475 degrees, thereby reducing the oxidation of resin, reducing the oxidation burn of workpieces, and prolonging the working life of grinding wheels at high temperature.

4 FeS2 + 11 O2→2 Fe2O3 + 8 SO2 
(2) 4 FeS + 7 O2→4 Fe2O3 + 4 SO2 

400-475 degrees is a limit that the grinding wheel can easily reach. The above reaction creates an oxygen-free and hypoxic environment for the grinding wheel at the micro level, thereby improving the high-temperature performance of the grinding wheel.
Decomposition reaction occurs at 650-degree heat absorption, thereby reducing the working temperature of the grinding wheels.

FeS2→FeS + S 
(3) It enters the melting state at about 1100 degrees, which becomes a good lubricant to protect the grinding wheel FeS(s)→FeS(l).

(4)Sulfur, sulfur dioxide and sulfur trioxide react with the workpiece surface to form FexSy:


S: 48%min, FE: 42%min, SIO2: 3.0%max, PB: 0.1%max,

ZN: 0.1%max, AS: 0.1%max, . C: 0.3%max, CU: 0.2%max,

H20: 1.0%max, SIZE: 95%min

Granularity: (0-3)mm/(3-8)mm/(3-15)mm/(15-50)mm or other particle size.

Packing: 25KG/500KG/1000KG/BAG or 1000KG/BAG or other packaging.

Note: if there are special requirements, the product can be customized according to clients` requirements.

Iron Sulphide For Resin Grinding Wheel---LHT(SL)

Iron sulphide for resin grinding wheel Pyrite, Iron pyrites, pyrites lump, Ferro sulphur, Pyrites powder