First, the purpose
In order to ensure that the mold can produce qualified products, it is put into production normally to ensure the service life of the mold and meet the production and use requirements of the product design. The specification recognizes the standard of the mold from the aspects of product quality, mold structure, injection molding process requirements, etc. Based on this, the mold quality is evaluated, and the test procedure and precautions of the plastic mold are understood through training.
First familiar with the following materials, familiar with the key process of the test process and the test process.
Through the practice of the test model, learn the actual test process.
Inspect the mold appearance, mold material, casting system, mold, reset, extraction core, pick-up, exhaust, water transport system, injection molding process system, product appearance, size, function coordination to accept.
Three: Things to be clear before the test and during the test
As a mold acceptance party, things should be clear before the test and during the test.
Before the test:
(1) In the mold design stage: When communicating with the mold manufacturer in technical communication, it is necessary to confirm the applicable machine of the lower mold, the capacity requirements, whether to use the automatic production method, the mold life requirement, the shrinkage rate setting of the product material, and the mold structure ( According to the mold feeding method, the design of the PL line.
For important parts, the mold manufacturer is also required to perform a mold flow analysis to better predict and evaluate the defects that may occur in the production.
(2) The mold is completed, before the first test
Confirm whether the mold has a strong protection device (such as whether there is a forced abduction mechanism, or a thimble limit switch mechanism, these mechanisms are devices that ensure that the mold is not damaged to the mold under abnormal conditions)
Confirm that the mold ejection and retraction mechanism is installed. The pull-out mechanism is common in the ejector mechanism (whether the tie rod is balanced, the number of the tie rods is not enough to be confirmed) and the cylinder mechanism, sometimes there will be gas-assisted ejector assistance, and whether the nozzle needle has a Z-shaped pull The cold material level is found (there are often nozzles in the production of the six workshops). The end of the return rod is flat and there is no spot welding. There is no gasket at the bottom of the embryo head, spot welding, and the mold of the slider should be opened at the movable part of the slider. After the mold is installed on the injection molding machine, do not rush to immediately perform injection molding and mold adjustment. Instead, the technician is required to set the injection molding machine in the manual operation position, and the technician is required to manually perform each movement of the mold.
1. The ejector pin is ejected (determine whether the ejecting is smooth and balanced, whether the position is enough for the product to fall off, and whether an abnormal friction sound is emitted)
2. The thimble is reset (whether the thimble can be repositioned, if not, it will cause damage to the front mold cavity, and should be checked in time before proceeding to the next step)
3. Whether the thimble is installed in a limited position and whether the slider can slide in place.
4. Is it possible to mold and open the mold normally?
After the above preliminary work is confirmed, the mold adjustment can be performed.
In addition, in addition to the size and appearance of the sample itself, it is also combined with an overall assembly confirmation. Therefore, every time you try to mold, you must try to bring all the assembly parts together. The overall assembly confirmation can provide a more direct understanding of the assembly problems existing in the test product, and it is more convenient to analyze the modified solution for the existing assembly problems. You can avoid the complexity and save time.
The acceptance of the mold, the introduction of the new mold before the test and the test process are as follows:
1. Make sure that all the problem points have been resolved, and that there is no problem after the normal production has been performed on a specified machine (for example, 5,000 beer).
2. Defining the wearing parts of the mold, and requiring the mold shop to provide spare parts for the wearing parts to prevent the production from being damaged due to the damage of the wearing parts.
3. It is required to apply anti-rust paint to the exposed part of the mold and make the name of the mold.
4. The surface of the product is not allowed to be defective: lack of material, charred, white, material, burr, foaming, whitening (pull, break), shrinkage, snake pattern.
Second, the appearance of the mold
1. The name of the mold is complete, the characters are clear and arranged neatly.
2. The cooling nozzle should not protrude from the surface of the mold base.
3. The cooling nozzle should have an ingress and exit mark.
4. The English characters and numbers should be greater than 5/6, and the position should be about 10mm at the nozzle. The writing should be clear, beautiful, neat and evenly spaced.
5, 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.
6. The mounting leg of the supporting leg is fixed on the formwork through the supporting leg, and the excessively long supporting leg is used to fasten the externally threaded column to the formwork.
7. 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.
8. 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. Unless otherwise required.
9, the mold dimensions should meet the requirements of the specified injection molding machine.
10. The mold with the orientation requirement should be marked with the arrow on the front or rear template to indicate the installation direction.
11. The surface of the formwork should not have pits, rust, excess rings, water vapor, oil holes, etc., as well as defects affecting the appearance.
12. The mold should be easy to hoist and transport. When hoisting, the mold parts must not be disassembled. The lifting ring must not interfere with the water nozzle, oil cylinder and pre-reset rod.
Third, 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 have an oil groove and the surface should be nitrided.
4. All ejector pins should have anti-rotation positioning, and each ejector pin 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, the wave screw can be used. The cylinder core must have a travel switch.
8. The slider core is generally inclined, 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. There should be a wear plate under the large slider with a slider width of more than 150 mm. The wear plate is 0.05~0.1 mm higher than the large surface, and the oil groove is opened.
10. The ejector pin should not be strung up and down.
11. If the bar is attached with a barb, the direction of the barb should be consistent, and the barb is easy to remove from the product.
12. 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 standard requirements.
13. When the product is ejected, it is easy to follow the oblique top, and the ejector pin should be grooved or etched.
14. 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.
15. The three-plate mold gate plate slides smoothly, and the gate plate is easy to open.
16. 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.
17, the oil passage airway should be smooth, hydraulic ejection reset should be in place.
18. The exhaust port should be opened at the bottom of the guide sleeve.
Fourth, cooling, heating system
1. The cooling or heating system should be fully ventilated.
2, the seal should be reliable, the system should not have leakage under the pressure of 0.5MPa, 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 flow 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 under the premise of ensuring 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 is on the gate of the gate plate. The diameter of the runner entrance should be less than 3 mm. The ball head has a step of 3 mm deep into the gate plate.
5. The gate and runner should be machined according to the size requirements of the drawings, and the grinding machine is not allowed to be processed.
6. The gate of the gate should be in accordance with the specifications.
7. There should be an extension at the front end of the runner as a cold pocket.
8. The Z-shaped inverted buckle of the pulling rod should have a smooth transition.
9. The splitter on the parting surface should be round, and the front and rear modes should not be misaligned.
10. The latent gate on the ejector rod should have no surface shrinkage.
11. The diameter and depth of the cold hole of transparent products should meet the design standards.
12. The material head is easy to remove, the appearance of the product has no trace of the gate, and there is no residual material at the assembly of the product.
13, bent hook latent gate, two parts of the block should be nitrided.
Sixth, molding part, parting surface, exhaust groove
1. There should be no defects such as unevenness, pits, rust and other effects on the surface of the front and rear molds.
2. The parting surface is kept clean and tidy, and there is no depression in the sealing part.
3. The depth of the venting groove should be smaller than the overflow value of the plastic. The groove can be deepened by about 10mm from the dividing surface.
4, the insert fits in place, the placement is smooth, and the positioning is reliable.
5, inserts, inserts, etc. should be securely positioned and fixed, the round pieces have a rotation stop, and the copper blocks and iron pieces are not placed under the inserts.
6. The end face of the ejector pin is consistent with the core.
7. There are no defects such as undercut and chamfer in the front and rear mold forming parts.
8, multi-cavity mold products, the left and right parts are symmetrical, should be noted L or R, the location and size requirements, should meet the requirements, generally in the place that does not affect the appearance and assembly.
9, mold frame locking surface fit (flying mode) should be in place, more than 75% of the area encountered.
10. The ejector rod should be placed close to the side wall and beside the ribs and bosses, and use a larger ram.
11, for the same piece should be noted the number 1, 2, 3, etc. in order to distinguish.
12. Each touch surface, insert surface, and parting surface shall be matched with the test (flying mold) in place.
13. The parting surface sealant part should meet the design standards.
14, leather lines and sandblasting should meet the requirements evenly.
15. The product with the required appearance shall have anti-shrinkage measures for the screws on the product.
16. 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.
Seven, 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 of the mold injection molding production, the injection speed of the three-quarter 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 process of injection molding, the removal of products and nozzles should be easy and safe (the time is generally less than 3 seconds).
7. The mold with insert products is easy to install and secure for inserts during production.