Injection mold manufacturing process and the basic processing process analysis
The injection mold manufacturing process mainly includes.
Acceptance of the task.
Mold design.
Mold manufacturing.
Mold inspection and mold trial.
Mold modification and repair.
Mold maintenance.
I. Acceptance of tasks
Plastic mold making, first of all, the customer engineers provide product drawings to the mold manufacturer, the manufacturer through the molding plastic production task requirements, the process of collecting, analyzing, digesting product data, this is the acceptance of the task.
1. Plastic part production requirements
Understand the use of the part, process, dimensional accuracy and other technical requirements. For example, what are the requirements of plastic parts in terms of appearance, color transparency, and performance, whether the geometry, slope, and inserts of plastic parts are reasonable, the allowable degree of molding defects such as fusion marks and shrinkage, and whether there is post-processing such as painting, plating, silk-screening, and drilling.
Estimate whether the molding tolerance is lower than the tolerance of the plastic parts, and whether the plastic parts can be molded to meet the requirements. In addition, to understand the plasticization of plastic and molding process parameters.
2. Process information
Understand the requirements of glue feeding method, brewer model, plastic material properties, mold structure type, etc.
The molding material should meet the strength requirements of the plastic parts, have good fluidity, uniformity and isotropy, and thermal stability. According to the use of plastic parts and whether post-processing, molding materials should meet the requirements of dyeing, metal plating conditions, decorative properties, necessary elasticity and plasticity, transparency or reflective properties, gluing (such as ultrasound) or welding, etc.
3. Selection of molding equipment
Injection capacity, clamping pressure, injection pressure, mold installation size, ejector device and size, nozzle hole diameter and nozzle sphere radius, gate sleeve positioning ring size, mold maximum and minimum thickness, mold stroke, etc.
4. Specific structure plan of mold
Two-plate mold, three-plate mold. Whether the mold structure is reliable, whether it meets the process technology of plastic parts (such as geometry, indicate finish and dimensional accuracy, etc.) and production economic requirements (low cost of parts, high production efficiency, mold can work continuously, long service life, labor saving, etc.).
Second, mold design
1.Rubber parts arrangement
The arrangement of plastic parts is to arrange one or more plastic parts according to the customer’s requirements according to the reasonable injection process and mold structure.
The arrangement of plastic parts is complementary to the mold structure and plastic technology, and directly affects the later injection molding process, so the arrangement must consider the corresponding mold structure and adjust the arrangement under the condition of meeting the mold structure.
From the perspective of injection molding process, the following points should be considered.
a、Runner length.
b. Runner waste.
c、Gate position.
d、Glue feed balance.
e, cavity pressure balance.
From the perspective of mold structure, the following points need to be considered.
a、Meet the requirements of sealing glue
b. Meet the space requirements of the mold structure: shovel base, row position, slanting top and other space requirements, whether the mold structure is strong enough, whether multiple moving parts interfere, the location of the cylinder to avoid the location of the top stick hole, etc.
c, fully consider the screws, cooling water and ejector device: the row position needs to pay attention to the impact of screws, ejector for cooling water holes.
d. Whether the mold length and width ratio is coordinated: the mold should be as compact as possible with proper length and width ratio, and the installation requirements of injection machine should be considered.
2. Quotation drawing and ordering material
a. The quotation drawing is the initial design of the mold, and also provides reference instructions for the mold ordering. The quotation drawing is a relatively detailed identification of the mold embryo, its structure and the size of the mold flesh on the basis of the original mold layout.
b. Order material is based on the quotation, draw the sketch of mold blank and fill in the order form.
The ordering material needs to pay attention to the various requirements of the mold, and to choose various mold materials appropriately.
3.Mold structure design
The mold structure is determined by the type of injection machine and the characteristics of the rubber parts. The design focuses on the following aspects.
(1) Technical specifications of the injection molding machine.
(2) The process performance of the plastic.
(3) The pouring system, including runners, gates, etc.
(4) molding parts.
(5) common structural parts.
(6) line position mechanism.
(7) Ejector mechanism.
(8) Mold temperature control.
(9) exhaust.
(10) mold material.
Mold design needs to consider various factors and choose reasonable structure form to meet the purpose of mold forming.
a、Rowing of rubber parts
In the 3D design stage, at this time, the arrangement is made according to the 2D arrangement at the beginning of the design for more in-depth design.
b、Division of mold
Choose the correct parting surface, consider the sealing distance, build the reference plane, balance the lateral pressure, flatten the nozzle touching surface, small hole touching and inserting through processing, avoid producing sharp steel, comprehensive consideration of product appearance and so on need to consider well.
c、Calibration and improvement of mold strength
In order to meet the normal work of the mold, not only to check the overall strength of the mold, but also to check the strength of the local structure of the mold.
For specific institutions to make certain improvements to improve the local strength.
d、Design of mold parts
Mold parts can be divided into molding parts and structural parts according to their roles.
Parts. Forming parts are directly involved in the formation of the cavity space structural parts, such as concave mold (cavity), convex mold (core), inserts, line position, etc.; structural parts are used for installation, positioning, guidance, ejector and forming to complete a variety of action parts, such as positioning rings, muzzle, screws, draw bar, ejector, seal, fixed distance pull plate, hook, etc..
The splitting of inserts, the main considerations are as follows.
(1) can not produce sharp steel, thin steel
(2) easy to process
(3) easy to trim the size and maintenance
(4) to ensure the strength of molded parts
(5) easy to assemble
(6) can not affect the appearance
(7) comprehensive consideration of cooling (do inserts after the local cooling difficulties, to consider its cooling situation)
Structural parts design, the layout of the ejector pin and water transport layout generally follows the principle of first cloth ejector pin, then cloth water transport, and then adjust the ejector pin. But the actual production process, often to consider the case of mold change, mold production is not immediately after the completion of the water transport, only after the completion of a certain change in the mold and then according to the change after the situation to open.
The arrangement of the cylinder.
The cylinder is generally applied to the molding column position, in addition to the deeper bone position ejector pin ejected easily top white, also available cylinder plus bone to assist the ejector. In general, the wall thickness of the cylinder >= 1mm, when ordering the cylinder and the cylinder needle together with the order.
In the structure design, the height of the column try not to be too high, or the syringe needle is easy to punch bent, difficult to eject, as follows.
For other structural parts, such as positioning ring, chirp, screws, pulling rod, seal, fixed distance pulling plate, pulling hook, spring design and use, interested parties can find some information to understand themselves.
e、The production of mold drawings
Mold drawing is an important document to transform the design intention into mold making, generally it should be drawn according to the national standard, in addition, it also needs to combine the customary drawing method of each factory.
Mold drawings include the total assembly structure and its technical requirements, in addition to all the parts including various inserts of the parts diagram.
Three, mold manufacturing
1、Programming and electrode removal
After the mold design is completed, it is necessary to prepare CNC program according to the processing situation of each part and whether to remove the electrode EDM processing.
2、Machining
The mechanical processing of the mold includes CNC processing, EDM processing, wire cutting processing, deep hole drilling processing, etc. Mold in the mold embryo and material order back only rough processing state or just steel, then must be based on the mold design intention, a series of mechanical processing, made of various parts.
CNC processing, computer numerical control, that is, CNC machining center, its requirements include a variety of processing procedures, tool selection, processing parameters and so on requirements, interested parties can find relevant information to learn.
EDM processing, is the electric discharge machining, which is the use of electric discharge corrosion material to achieve the required size of the processing process, and therefore can only be processed conductive materials. The electrodes used are generally copper and graphite.
Wire cutting is used for machining sharp corners.
Deep hole drilling is generally used in the processing of large mold water transport hole and the processing of the thimble sleeve hole.
3. Clamp assembly
Clamp in the mold making process plays a very important role, the work needs to run through the entire mold manufacturing process. Clamp work, fit die assembly, turning, milling, grinding and drilling all kinds of proficiency.
4. mold saving, polishing
Save mold, polishing is mold in CNC, EDM, clamping processing, mold assembly before the mold using sandpaper, oil stone, drilling plaster and other tool materials for mold parts processing.
Four, mold inspection and mold test
1.Inspection of mold
The process of mold fitting and assembly is actually considered as the inspection process of the mold, in the fit mold assembly, you can check whether the red dane is in place, whether the thimble sleeve is smooth, whether the mold has done wrong interference, etc.
2.Test mold
After the mold manufacturing is finished, in order to test the condition of the mold and whether the structure of the rubber parts is good, it is necessary to test the mold on the injection machine. Through the test mold, we can understand the situation of the mold in the process of making beer and whether the structure of the rubber parts is good or not.
For the requirements of mold trial and the improvement of the defects of the rubber parts, please refer to other information.
V. Mold change and repair
After the mold trial, we will make changes according to the mold trial, and after the engineer confirms the plastic parts, the structure of the plastic parts should be changed accordingly.
Since the mold has been made, all the changes are more troublesome, and sometimes even more difficult than the redo, so we must find the best way to make changes according to the specific situation.
For the structure design, the structure change must try to understand the mold situation, whether to touch the water transportation, ejector pin, how to change the easiest, etc., can be combined with the relevant information before making the relevant mold change, if necessary, you can consult the mold group colleagues.
The processing of cooling system.
Cooling system processing (drilling water), the product generally requires the front mold water in the first mold change information need to be processed, after the mold water in the second mold change information need to be processed, but for the water to open or not on the beer for the greater impact of the case, such as PC material beer (need to play hot oil beer case), try to open before the first mold test.
Therefore, the structure design drawing stage to consider all kinds of situations, as far as possible to reduce the workload of mold changes, so that the opening of the water can be normal operation, beer size as soon as possible to determine.
Modification of the product structure.
Add bone, add column, structure overhaul redo inserts.
Original bone plus or minus rubber, column shift, screw column increase or decrease, height increase or decrease, batch front trimming, etc.
Six, mold maintenance
Because the mold works under high temperature and pressure, and long term contact with air, it is very easy to produce rust phenomenon, so it is necessary to do a good job of maintenance of the mold, when not making beer, it is necessary to play anti-rust oil, grease, etc.
In addition, because the steel of the mold has a certain service life, as well as the mold structure design is unreasonable, some thin steel structure or the thimble of the cylinder will appear chipped and broken, etc., in the later maintenance must be constantly to maintain, repair.
