Because of different forming die has been applied many fields, together with professional mold manufacturing technology are also some changes over the years, so in this part, summarizes the vacuum forming mould of the general design rules.
Vacuum forming mould design including the batch size, molding equipment, precision condition, geometric design, dimensional stability and surface quality, etc.
1, the size of the batch experiment, mold production hours, wood or resin can be used for manufacturing.
However, if the mould is used to obtain products related to shrinkage, dimensional stability, and the data such as cycle time, should use the single cavity mold to experiment, and can ensure that can operate under the condition of production.
General use gypsum mold, copper, aluminum or aluminum
Steel alloy manufacture, rarely use aluminum -
2, geometric design, the design, often have to consider the dimensional stability and surface quality.
Products design and dimensional stability, for example, require the use of cavity die,
, but require the products of the high gloss surface requires the use of male mold (
So that parts order will comprehensively considering these two points, so that products can be in the best conditions for production.
Experience has shown that do not conform to the actual processing conditions of design is often fail.
3, size stability, in the process of forming, in contact with the mould surface mould parts dimension stability is better than the left.
If in the future due to the need of the material stiffness requirements by changing the thickness of the material may lead to male mold conversion to female die.
Plastic pieces of the size tolerance of not less than 10% of the shrinkage rate.
4, on the surface of the plastic, the molding material to cover the scope, structure visible surfaces should be in contact with the mold shape.
If possible, don't contact with the mould surface bright and clean surface of the plastic.
Just like the female die manufacturing tub and wash tub.
5, decorate, if using mechanical level saw sawed off parts of the clamping side, on the height direction, there must be at least 6 ~ 8 mm allowance.
Other finishing work, such as grinding, laser cutting or jet, also must leave allowance.
Minimum clearance between the blade die cutting line, punching die when finishing the distribution width are also small, these are all pay attention to.
6, shrinkage and deformation, plastic shrinkage (
Such as PE)
And some plastic parts easy to deformation, no matter how to prevent, plastic parts in the cooling stage deformation will occur.
Under these conditions, be about to change the molding mold shape to fit in a geometric deviation.
For example: although plastic wall flat, but its benchmark center has deviated from 10 mm;
Can raise the mold base, in order to adjust the shrinkage deformation.
7, shrinkage, in manufacturing vacuum forming mould must take into account the shrinkage of the following factors.
(1) forming products contraction.
If you can't know clearly of plastic shrinkage rate, you must sample or with similar shape mold to get through experiment.
Note: this method can get shrinkage rate, can't get the deformation size.
(2) adverse effect caused by the contraction of intermediate medium, such as ceramics, silicon rubber, etc.
(3) the mold shrinkage of the materials used, such as shrinkage of casting aluminum.