10 Points analysis points for Mold Structure

Regarding the mold structure analysis, we can disassemble and analyze it from the following 10 aspects.We must first determine the overall mold structure, and then combine the customer’s requirements for the mold structure, from the analysis of the molded parts, the analysis of the pouring system, and the lateral extraction Analysis of the core mechanism, ejection system, temperature control system analysis, hot runner system, exhaust problem analysis and processing problems to carry out mold analysis.

1. The overall mold structure

What kind of formwork to use—a two-plate formwork, a traditional three-plate formwork, or a condensed three-plate formwork?
How to calculate the collision surface, parting surface, penetration surface, and line of parting.
To strengthen the mold structure, consider strengthening the mechanism that positions the fixed and moveable molds (such as the inner mold insert pipe position or side lock).
Whether it is essential to create a fixed-distance separation mechanism, pull the core laterally or construct a push piece fixing plate first reset mechanism.
Both the benefits and disadvantages have been completely examined for the four-sided core-pulling mold structure, regardless of whether the four-sided sliders are mounted on a mobile mold or a permanent mold.
Has the consumers been informed of the effect the separation line of the four-sided core pulling will have on the plastic part’s appearance?
How to solve the issue of plastic pieces with inconsistent wall thickness?
whether to raise the standard square iron and whether to thicken the standard guide post.
Whether to build a safety device and whether the auxiliary mechanism (hydraulic cylinder, water pipe junction, etc.) on the lower side of the mold touches the ground (such as a safety block or a foot, etc.)

2. Requests for mold structure for customers

Please confirm whether the customers have any requests for Injection Mold Machine, If have, Please guaranteed these points as follows.

The planned area of the plastic part * the melt’s pressure on the cavity * the injection molding machine’s clamping force * 80%.
Plastic part + condensate volume from the gating system rated injection volume * 80% of the injection molding machine.
Whether the injection molding machine’s requirements for the sprue sleeve’s dimensions and diameter.
The space between the tie rods equals the mold’s maximum width.

The maximum width of the mold = the width of the template + the length of the auxiliary mechanism protruding from both sides of the template;
Auxiliary mechanisms include oil (air) cylinders, springs, fixed-distance parting mechanism, push-piece fixing plate first reset mechanism, hot runner terminal box, pipe joints, etc.

e. Whether the push-out distance of the plastic part is sufficient, and whether the total thickness of the mold plus the mold opening distance meets the mold opening stroke of the injection molding machine.

f. In the first reset mechanism of the push-piece fixing plate, if the top rod of the injection molding machine is pulled back, the connection position, thread pitch, diameter, etc. that match the push-piece fixing plate must first be obtained from the customer.

3. Analysis of mold components

Whether there are small inserts, how to insert the inner mold inserts, whether there are any problems with the processing of the cavity and inserts, whether the inserts need heat treatment, whether the molded parts and templates are integral or split, and how to fix them if they are split.
Whether the parting surface of the molded part should be designed with the internal mold pipe position.
Whether the sharp corners of the plastic parts, the R angle, and the inclined surface of the inner mold inserts have been considered when the inner mold inserts are assembled.
What kind of steel is used for the formed parts?
Are there any special requirements on the surface of the core cavity, such as etching, sandblasting, or mirror polishing?

If etching is required:

Whether the pattern and number of the etching pattern are clear.
If there is an etching on the side wall, the draft slope should be selected according to the etching specification.
Whether the etching range is clear or not.
Whether the pattern and serial number of each part are one or two or more.
To avoid scratches and uneven color, etch should be avoided at the thin wall.
Will the etched area on the movable mold side or the etched area of electrode processing be reflected on the surface of the plastic part, making the surface rough and producing different colors?
What kind of sandblasting treatment (gloss treatment) should be applied after etching?
Full gloss 100% → glass sand semi-gloss 50% → glass sand + corundum matting 0% → corundum.

If sandblasting is to be done:

Whether the pattern and number of sandblasting are clear.
Whether the scope of sandblasting is clear.
When using one or more than two kinds of blasting, whether its form or number is clear.
Which type of blasting to use (corundum, glass, corundum + glass)?

4. Analysis of the gating system

Use a hot runner or ordinary runner, use a side gate or point gate.
How to choose the form and size of the main channel and the branch channel.
Whether the size, location, quantity, etc. of the gate are reasonable.
Has the impact of the gating system on the molding cycle been considered?
Whether the exhaust of the pouring system has been considered.
Whether the weight percentage of the pouring system aggregate to the entire plastic part is reasonable.
Have you considered the balance of the flow path?
Whether the form of the pull rod is reasonable, and whether the impact on the appearance after the gate is removed is acceptable to the customer.
The method of taking out the condensate of the pouring system is automatic drop, manual removal, or mechanical hand removal

5. Analysis of the lateral core-pulling mechanism

Whether it is necessary to make a lateral core-pulling mechanism, and whether it can be replaced by pillow-lifting, insertion, or other structures.
Whether the slider is in the moving mold or the fixed mold, the moving mold should be given priority.
How to choose the best direction for lateral core pulling.
How to ensure the guidance and positioning of the slider.
Where is the power source of the slider, whether it is an inclined guide column, hydraulic pressure, spring, bent pin, or T-shaped buckle?
How to determine the inclination angles of inclined guide pillars, inclined sliders, bent pins, or T-shaped buckles.
How to ensure that the wedge block of the slider has sufficient locking force when it is subjected to a large area of plastic injection pressure.
How to ensure the convenience of processing, assembly, and maintenance of the core-pulling mechanism.

6. Mold Structure: Launch System

Where push parts must be added to plastic parts, such as long studs, high ribs, deep grooves, corners, etc. are the places with the largest tightening force.
What is the launch schedule and whether it is necessary to increase the height of the square iron?
Whether it is necessary to adopt unconventional push-out methods, such as push block push-out, pneumatic push-out, secondary push-out, internal thread motorized de-molding, etc.
Whether to design the first reset mechanism of the push-piece fixing plate.
Whether to design the guide post of the push-piece fixing plate.
Whether it is necessary to design a delay release mechanism.
How to ensure the appearance of the push-out system of transparent plastic parts.
If the mold is to be fully automated, how to ensure 100% reliability of molding?
For large plastic parts, whether there will be a vacuum in the plastic part and core cavity when pushing out.
Whether it is necessary to design the ejection mechanism of the fixed mold, and whether it is necessary to design the intake mechanism.
After the plastic part is pushed out, how to take it out, whether it is taken by hand, by a mechanical arm or automatically dropped.

7. The analysis of the temperature control system

Recognize the plastic part production program and whether the customer has specific injection cycle needs.
Whether the customer has any precise criteria for the types of water pipe joints to be utilized and whether those joints need to be incorporated into the formwork.
Whether there are any locally hot areas of the mold and whether cooling efforts should be directed there.
According to the characteristics of the molded plastic and the size of the plastic part, what should be the mold temperature range during the actual production of the mold?
How can each part achieve a simultaneous cooling effect?
Which medium is used in the cooling (heating) circuit, whether it is ordinary water, chilled water, warm water, or oil?
Whether the cooling circuit is connected to the internal mechanism (bolt, push rod, etc. ejection system, inner mold insert) or external mechanism (screw hole of lifting ring, Hot runner temperature control box, hydraulic cylinder, etc.) interference.
How to set up the cooling water circuit and choose between using standard cooling techniques such as water r wells, jets, or inlaid beryllium copper to calculate the water pipes’ diameter.
Whether the cooling circuit processing is convenient and whether it takes too long.
How to construct the cooling system to prevent standing water.
Establish a separate cooling circuit close to the sprue sleeve, if necessary.

8. Mold Structure: Hot Runner System

If the hot runner system is used, then:

Whether the customer has clear instructions on the material of the temperature sensor.
Whether the customer has clear requirements for metal connectors and terminals.
How to choose the most reasonable heating elements such as heating rods and heating coils.
How to determine the capacitance of the heating element.
How to arrange the wiring of the temperature sensor.
How to avoid the occurrence of open circuits, short circuits, insulation, etc. of the heating element.
How to choose the gap of the hot nozzle should try to use standard parts to shorten the procurement cycle.
How to achieve thermal insulation of the hot runner plate.
How to assemble and position the hot runner plate, and whether it is convenient to assemble and disassemble.
How to deal with the problem of thermal expansion.

9. Mold Structure: Examination Of Exhaust Issues

Whether the moving mold side or the fixed mold side is suited for the exhaust groove on the separating surface.
Is there any trapped air in the cavity in particular?
How to vent areas with thin or thick walls, as well as how to vent interior mold inserts and ribs.
Is it necessary to use a special exhaust technique, such as an air valve exhaust, exhaust plug exhaust, or exhaust from steel that is permeable to air, etc.
Whether the end of the gating system needs to be designed with an exhaust groove.

10. Mold Structure: Problems In Processing

Whether there is an opportunity for improvement, the mold core cavity can be treated, and the plastic part’s structural shape is suitable.
Whether the customer has approved the clamp line of the insert on the plastic part’s surface.
The need for, and method of, inlaying at the reinforcing ribs.
Whether there is any trouble with wire cutting, EDM, CNC processing, or other processing.

If engraving is required:

Whether the customer has provided the script and negatives.
What is the magnification of the film?
Whether the font or symbol of the plastic part is concave or convex.
The choice of engraving method is direct engraving machine engraving, electric discharge engraving, beryllium copper extrusion insert, or numerical control (NC) milling machine processing.
Whether it is necessary to add shrinkage to the size of the engraving plate.

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