Basic knowledge of mold

- Jun 06, 2019-

Production process
The mold is a model, according to this model to make products, but how molds are produced, may be most of the mold professionals can not answer. Molds have played an irreplaceable role in our lives, Most of our daily necessities can not be separated from molds, such as computers, telephones, fax machines, keyboards, cups, and other plastic products. In addition, covers such as automobiles and motorcycle engines are also made from molds. One car needs more than 20,000 molds of all kinds. Therefore, the role of modern life molds can not be replaced. As long as mass production is inseparable from molds.
So how is the mold made?
The following is a simple introduction to the production process of modern molds.
1) ESI(Early participation of Earlier Supplier vendors): This stage is mainly a technical discussion between customers and suppliers on product design and mold development. The main purpose is to allow suppliers to clearly understand the design intentions and accuracy requirements of product designers. At the same time, it also allows product designers to better understand the ability of mold production and product process performance, so as to make a more reasonable design.
2) Quotation: Including the price of the mold, the life of the mold, the turnover process, the number of tons required by the machine, and the delivery date of the mold. (More detailed quotations should include product size weight, mold size weight, etc.. ))
3) Order(Purchase Order): Customer orders, delivery of deposits, and acceptance of supplier orders.
4) Die Production Plan and Scheme Arrangement: This stage requires a response to the customer for the specific date of delivery of the mold.
5) Design: Possible design software is Pro/Engine, UG, Solidworks, AutoCAD, CATIA, etc..
6) Procurement materials
7) Machining: The processes involved are roughly cars, gongs(milling), heat treatment, grinding, computer gongs(CNC), EDM, wire cutting(WEDM), coordinate grinding(JIG GRINGING), laser engraving , polishing and so on.
8) Mold Assembly(Assembly)
9) Trial Run
10) Model Assessment Report(SER)
11) Sample Evaluation Report Approval(SER Application)
Mould manufacturing
The requirements of mould design and manufacture are: accurate size, clean surface; Reasonable structure, high production efficiency, easy automation; Easy to manufacture, high life expectancy and low cost; The design meets the needs of the process and is economical and reasonable.
The structure design and parameter selection of the die must consider such factors as rigidity, orientation, unloading mechanism, positioning method, Gap size and so on. Vulnerable parts on the die should be easily replaced. For plastic mold and die casting mold, it is also necessary to consider the reasonable pouring system, molten plastic or metal flow state, and the position and direction of entering the cavity. In order to increase productivity and reduce the loss of stream pouring, a multi-cavity mold can be used to complete multiple identical or different products at the same time in one mold. In mass production, high efficiency, high precision and high life of the mold should be used.
The stamping die should adopt multi-position step advance die, can use the cemented carbide inlaid block step advance die, in order to increase the life. In small batch production and new product trial production, simple dies with simple structure, fast manufacturing, and low cost should be used, such as combination die, thin plate die, polyurethane rubber die, low melting point alloy die, zinc alloy die, ultra-plastic alloy die and so on. Mould has begun to use computer-aided design(CAD), which is to optimize the design of molds through a set of computer-centered systems. This is the direction of mold design.
According to the structure characteristics, the mould manufacturing is divided into planar punching die and spatial cavity die. Punching die use the dimension of convex die and concave die precise match, some even have no gap match. Other forging molds such as cold extrusion molds, die-casting molds, powder metallurgical molds, plastic molds, rubber molds, etc. are all molds used to form three-dimensional workpieces. The type of cavity mold has dimensions requirements in three directions: length, width, and height. The shape is complex and difficult to manufacture. Mold production is generally a single piece, small batch production, manufacturing requirements are strict, accurate, more sophisticated processing equipment and measurement devices.
Plane punching die can be used for EDM initial forming, and then grinding with forming, coordinate grinding and other methods to further improve the accuracy. Form grinding can be made by optical projection curve grinder, or a plane grinder with indentation and repair wheel mechanism, or by special grinding tool on a precision plane grinder. The coordinate grinder can be used for the precision positioning of the mould to ensure precision aperture and hole spacing. Computer CNC(CNC) continuous trajectory coordinate grinder can also be used to grinding any curved shape of the convex and concave die. The type of cavity mold is mostly processed by imitation milling machine, EDM and electrolysis. The machining quality of the cavity can be improved by the combination of simulation milling and numerical control and the addition of three-way flat head device in EDM. The production efficiency can be improved by adding inflatable electrolysis in electrolysis processing.
Commonly Used Software
Shaped mold
PTC's EMX, Siemens's NXMold Wizard, CimatronE, Delcam Molmaker, Missler's Topsolid Mold, Think3's Mold Design, Manusoft's IMOLD, R& B's MoldWorks et al..
Hardware Mould
PTC's PDX, Siemens's NXProgress Die Design, Logopress 3 of Logopress, 3D QuickWorks Limited 3D QuickPress, R& B Mold &; Die Design's MoldWorks, Missler's Topsolid Progress, etc..
Process performance
The manufacture of molds generally has to go through several processes such as forging, cutting, and heat treatment. In order to ensure the manufacturing quality of the mould and reduce the production cost, the material should have good malleability, cutting, quenching, quenching and grinding; It should also have a small oxidation, decarbonization sensitivity and quenching deformation cracking tendency.
1. Forgability: It has low thermal forging deformation resistance, good plasticity, wide forging temperature range, and low tendency to forging and cracking and precipitation of reticular Carbide.
2. Annealing process: The spheroidal annealing temperature range is wide, the annealing hardness is low and the fluctuation range is small, and the spheroidal rate is high.
3. Cutting machining: The cutting amount is large, the tool loss is low, and the machining surface roughness is low.
4. Oxidation, decarbonization sensitivity: high temperature heating when the anti-oxidation heat, slow decarbonization, not sensitive to the heating medium, produce a small tendency for the point.
5. Hardness: After quenching, it has a uniform and high surface hardness.
6. Hardenability: After quenching, a deeper quenching layer can be obtained, and a tempered quenching medium can be used to harden.
7. Quenching deformation cracking tendency: conventional quenching volume changes little, shape warping, slight distortion, abnormal deformation tendency is low. The sensitivity of conventional quenching cracking is low, and it is not sensitive to quenching temperature and workpiece shape.
8. Grindability: Grindability: Grinding wheel relative loss is small, no burn limit grinding amount is large, not sensitive to wheel quality and cooling conditions, not easy to wear and grinding crack.
Use Performance
1. Low density: The low density of plastics is important for reducing the weight of machinery and equipment and energy conservation, especially for vehicles, ships, aircraft, and space vehicles.
2. High specific strength and specific stiffness: The absolute strength of the plastic is not as high as that of the metal, but the density of the plastic is small, so the specific strength(σ B / Hey) and specific stiffness(E / Hey) are quite high. In particular, reinforced plastics made of a variety of high-strength fibrous, flaky and powdered metals or non-metals as fillers have higher specific strength and stiffness than metals.
3. Chemical stability is good: Most plastics have good acid, alkali, salt, water, and gas properties. Under normal conditions, they do not react chemically with these substances.
4. Good electrical insulation, thermal insulation and acoustic insulation.
5. Good wear resistance and self-lubricating: plastics have small friction coefficient, good wear resistance, good self-lubricating, plus high specific strength, small transmission noise, it can work effectively in liquid medium, semi-dry or even dry friction conditions. It can be made into machine parts such as bearings, Gears, cams and pulleys. It is very suitable for