With the rapid development of the plastics industry and the continuous improvement of general and engineering plastics in terms of strength and accuracy, the application range of plastic products is also expanding, such as:Household appliances, instrumentation, construction equipment, automotive industry, daily hardware and many other fields, the proportion of plastic products is rapidly increasing. It has brought different requirements to the plastic mold processing technology,A good job
Documentation can affect production costs and product quality. The following suggestions are made for the preparation of plastic mold processing technology:The basic principles of preparing plastic mold process. According to their own human and material resources and customer provided data or drawing requirements, as soon as possible to prepare feasible process documents, to produce high quality products，It is usable. In the framework of this basic principle, fast, good, province is the core content, which runs through the entire preparation.
Quick":It requires the shortest time to prepare the shortest process documents, the work should pay attention to the following four points:
1、The technician should be able to know the machine tool equipment of the unit, the technical level, it is best to operate each machine tool, understand the processing very well, to adapt to the complexity and particularity of the mold parts, to get a drawing, can quickly determine the best processing process, improve the speed.
2、Determine a reasonable minimum machining allowance. Between the upper and lower processes and the rough and fine processes, the necessary processing allowance is set aside to reduce the processing time of each process.
3、Because the mold parts are mostly single pieces, small batches, and process cards can not be like batch products- -As careful and detailed, but to strive to understand, no omissions, key processes to explain clear processing precautions, write operational guidance, in order to reduce the operator's adaptation time, reduce processing errors.
4、For the fixture, measuring tools and auxiliary tools needed in the processing process, they should be designed and prepared in advance.
“good”:It requires the technologist to be able to write the most reasonable and best process documents to prevent problems in the processing process, and it is also one of the standards to measure whether a technologist is excellent. The following points should be noted:
1、Reasonable arrangement of heat treatment process. mould-product-One characteristic is the mechanical properties of the material, the heat treatment requirements are very strict, the key parts such as the die and the fixed plate, in the beginning stage to arrange annealing, improve the processing performance, after quenching, to carry out aging, eliminate stress and deformation.
2、Strictly distinguish rough finishing techniques.-As such, the division of rough and fine processes is determined by the heat treatment process, and the processing after the final heat treatment is mostly finished. The allowance should be arranged in the roughing stage as far as possible to reduce the loss of the tool and the loss of the electrode and electrode wire using electric machining.
3、Pretreatment process measures should be used. towards- - Some parts with more material removed in the middle, such as the concave die, the punch fixing plate, should be used before finishing0.5 mmAround, the first processing of the roughly shaped cavity, and then quenching aging, and then finishing method to eliminate the processing of internal stress deformation. For some thin-walled parts, such as discharge sleeves, a reinforcing process is pre-machinedTaiwan,To prevent machining clamping deformation.
4、Appropriate processing benchmarks are set aside. In the production often meet the problem that the processing base can not coincide with the design base, at this time, it is necessary to pre-process a process base in order to facilitate the processing of each process. For high-precision products such as progressive dies, dimensional accuracy conversion should be carried out.
5、Technical terms also need to be adopted. In the process document to make full use of well-known professional terms and processing expression methods, clearly convey the processing intention, to avoid color and "processing to drawings", "shape scale tolerance to requirements" and other vague language, to achieve the organic combination of process and drawings, so that the parties understand what should be done,
How can it be done so that it is also easy for the inspectorsprovince:It is necessary to fully save manpower, material and financial resources, and improve unit production efficiency. The following points should be noted:
1、Using the point of view of machining technology and integrated research, for single pieces and small batches of products such as molds, we should adopt the principle of centralized process processing, arrange processing on a machine tool as far as possible, shorten the process flow, which can reduce the repetitive labor time such as clamping, drawing, calculation, reduce the time of rotation and inspection, and improve production efficiency.
2The working hour quota of each machine tool processing is fully estimated, and the slow one can be avoided as quickly as possible, and the roughing one can be solved,
Never on the finishing machine, which is also conducive to protecting the accuracy and service life of the machine tool, saving costs.
In the mold parts, there are more plate parts, mainly fixed plates, upper and lower templates, discharge plates, cushion plates, etc., and the processing of such parts has a- Some commonalities, taking the fixed plate of the progressive die as an example, its process flow can be summarized as:laying-off 7forge7anneal(normalizing) 7matte7Rough grinding7 Machining center7quench7Semi-finished grinding7ageing( Stress relief annealing)7finishing7Wire cutting, electric spark. Shaft mold parts, mainly convex and concave die, its processing technology flow
-general: laying-off7anneal7car7quench(Or tempering)7Lapping hole7Rough grinding7ageing7finishing7A fitter.
After grinding, surface treatment such as bluing and nitriding can also be carried out according to needs. According to the different requirements of special-shaped parts, the preparation process can be treated differently, and the processing technology is optimized.
Third, the processing of assembly processing parts- - For the whole pair of molds, some parts need to be used due to the requirements of performance
To be combined processing. As a technician, it is very important to understand the assembly relationship between parts and parts and the role of parts in the whole pair of molds, so as to arrange the combination or matching process reasonably. For progressive die, part ruler Most of the inch is determined by the design, the parts that need to be matched for processing are few, and some of the parts and parts that need to be matched are prompted as follows:
1.Guide post and guide sleeve holes of upper and lower die frames. The height of the limit column when the die is pressed. The gap between the upper and lower knives when cutting and opening strips.
The preparation of mold processing technology has strong plasticity, but only Be willing to put your heart and mind into it, constantly summarize it, and constantly
Improvement, can be processed into inexpensive products.
The mold production process is as follows:
Drawing review and material preparation-Processing one mold frame processing one-Mold core processing - electrode processing - mold part processing - inspection- -Assemble a flying mold
-Trial mold production
A:Mold base processing: 1Number,2 A/BPlate processing，3Panel processing，4Processing of ejector pin fixing plate，
5Bottom plate processingB:Mold core processing: 1Flying edge,2Rough grinding,3Gun Bed PlusWork,4benching，5CNCRough machining,6heat treatment，7Fine grinding,8CNCfine machining，9Electrical discharge machining,10 Provincial modelC:Mold parts processing: 1Slider processing,
2Pressing block processing,3,Processing of diversion cone gate sleeve,4The processing details of the insert processing mold base shall be numbered uniformly, and the mold core shall also be numbered, which shall be the same as the number on the mold base-Consistent orientation ensures alignment during assembly, making it less prone to errors.A/BPlate processing(Instant fixed mold frame processing) ,a:A/BThe parallelism and verticality of the mold frame should be ensured during plate processing0.02mm，b :Gun bed processing:Screw hole, water hole, ejector pin hole, nozzle hole, chamferC:benching:Tapping teeth and trimming edges. Panel processing:Punch machine processing boring machine nozzle holes or processing material nozzle holes. Processing of ejector pin fixing plate:Gun bed processing:Ejector plate andBThe board is connected with a return pin,BDrill the top needle hole from top to bottom with the board surface facing upwards. The countersunk head of the top needle needs to reverse the bottom of the top needle plate and correct it. First, use a drill bit for rough machining, then use a gun knife for precision machining in place, and chamfer.5,Bottom plate processing:Gun bed processing:Scribing, correction, boring, chamfering. We need to add a strong pulling and lifting mechanism,(pour:Some molds require strong pulling and jacking, such as drilling screw holes on the ejector pin plate)
Mold core processing details（1）Rough machining of flying hexagonal edges:Processing on the gun bed to ensure verticality and parallelism, leaving grinding allowance
1.2mm
（2）Rough grinding:Large water grinding processing, first grinding the large surface, using a screwdriver to clamp and grind the small surface, ensuring that the perpendicularity and parallelism are within
0.05mmLeave margin on both sides0.6-0.8mm
（3）Gun bed processing:First, calibrate the machine head of the gun bed to ensure that it is0.02mmInside, correct and compress the workpiece, and first machine the screw hole,Top needle hole, threading hole, embedded needle countersunk head opening, machine nozzle or material nozzle hole, diversion cone hole chamfering, and then making water hole, gunRCorner. Fitter processing:Tapping teeth, typing code5) CNC Rough machining and external heat treatmentHRC48-52
7)Fine grinding; Large water mill processing to negative ratio of mold frame
0.04mm，Ensure parallelism and verticality within
0.02mmwithin
8) CNC fine machining
9)Electric discharge machining
10)Save mold, ensure smoothness, and control cavity size well。
11) Processing gate, exhaust, zinc alloy- -Under normal circumstances, the gate is opened
0.3-0.5mm，Exhaust on0.06-0.1mm,Aluminum alloy gate opening0.5-1.2mmExhaust on0.1-0.2,Plastic exhaust on·0.01-0.02Try to be wider and thinner. The manufacturing process of plastic molds can be roughly divided into the following steps:Process analysis of plastic products.
Before the mold design, the designer should fully analyze and study whether its plastic products meet the principle of injection molding processing, the need and system
The designer of the product has carefully negotiated and reached a consensus. This includes necessary discussions on the geometric shape, dimensional accuracy, and appearance requirements of the product, in order to avoid unnecessary complexity in mold manufacturing as much as possible. Mold structure design.-A set of high-quality molds not only requires good processing equipment and skilled mold manufacturing workers, but also a very important factor is the need for good mold design, especially for complex molds, where the quality of mold design accounts for a significant proportion of mold quality80%Above. An excellent mold design is:
Under the premise of meeting the requirements of customers, the processing cost is low, the processing difficulty is small, and the processing time is short.To achieve this, it is not only necessary to fully understand the customer's requirements, but also to have an understanding of the injection molding machine, mold structure, processing technology, and the processing capabilities of the mold factory itself.Therefore, to improve the level of mold design, the following points should be achieved:
1.Understand every detail in each mold design and understand the purpose of each part in the mold.
2.When designing, refer to similar designs in the past and understand the situation during mold processing and product production, and learn from their experiences and lessons.
3.Learn more about the working process of injection molding machines to enhanceThe relationship between deep molds and injection molding machines.
4.下The factory understands the processing technology of processed products and understands the characteristics and limitations of each type of processing.
5.Understand the mold test results and mold modification of their own design, learn lessons.
6.Try to use previously successful mold structures during design.
7.Understand more about the impact of mold water on products .
8.Study some special mold structures and understand the latest mold technologies.
Determine mold materials and select standard parts.
When selecting mold materials, in addition to considering the accuracy and quality of the product.
It is also necessary to combine the actual processing and heat treatment of the mold factory
Ability to make the right choice.in addition，To shorten the manufacturing cycle, make the most of existing standard parts as much as possible.
4、 Part processing and mold assembly.
In addition to providing the best structure and reasonable tolerance fit during design, the accuracy of the mold is,
Part processing and mold assembly are crucial
important.Therefore, the selection of machining accuracy and methods plays an absolute dominant role in mold manufacturing.
Ruler for formed products
The size error mainly consists of the following parts:
1.The manufacturing error of the mold is approximately1/3
2.The error caused by mold wear is approximately1/6
3.The error caused by uneven shrinkage of the formed part is approximately
1/3
4.The scheduled contraction is inconsistent with the actual contraction-The resulting error is approximately
/6
Total error=(1)+(2)+(3)+(4)
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