How to calculate the deformation force of plastic parts

1. In theory, deformation can be called contraction; There are two formulas, one is the actual shrinkage rate, the other is the calculated shrinkage rate. The difference between the two is not much. Usually, the calculated shrinkage rate is calculated by the calculated shrinkage rate. The calculated shrinkage rate (%) = (unidirectional dimension of plastic parts at molding temperature (mm) - unidirectional dimension of plastic parts at room temperature (mm)) / unidirectional dimension of plastic parts at room temperature (mm) * 100
there are four factors that affect the shrinkage rate: 1, Two plastic parts characteristics. Three mold structure, four molding process
self calculation! Look what you are~

2. The deformation of plastic procts is more complex, and the deformation of soft plastic procts is often related to time. But from the definition, if the plastic proct is deformed by force (sometimes the deformation of hard plastic procts is very small, which can be measured by instruments), the part that can return to the original shape of the plastic proct is called elastic deformation, and the part that cannot return to the original shape of the plastic proct is called plastic deformation.

3.

please click the input picture description

to make the insert, and increase the cooling water of the insert can rece the deformation of the proct

4. This question is a bit broad
I guess you want to ask how the dimensional tolerance of injection molded parts is reasonable

it is suggested to check from din16901 standard. The requirements of different materials and molds will be different
for flatness, other corresponding standards can be found in din16901 as reference
the following link shows the details of din16901< br />
https://wenku..com/view/66a83138bcd126fff7050b47.html

the structural design seems to be simple, but it takes a lot of effort to do it well, deeply and impeccably.

5. There are many reasons for deformation
mold: unreasonable intersection position, unreasonable waterway arrangement (some long procts need sectional drainage, warpage can be adjusted at that time), unreasonable ejection will also lead to proct ejection deformation... And so on
proct aspect: sometimes the design of the proct itself is unreasonable, for example, the proct is too long and without stiffeners, and the meat is uneven... And so on
molding: insufficient pressure holding time, too cold and too hot material temperature, too large and too small pressure will cause proct deformation
how to control: before design, a simple mold flow analysis can be done to determine the reasonable gate position and where warpage is prone to occur, and then ask the customer for detailed material property information to determine the reasonable molding process. However, to tell the truth, it ultimately depends on the experience of mold design. If you draw more, you will naturally know that warpage is easy to occur and solve problems in the design

6. Gravity, contraction. At the glass transition temperature, the molecular structure of plastics is chain like and stable. At the softening point, the molecular structure is not chain like and disorderly arranged. When the temperature reaches the melting point, the material will flow like glue under the influence of gravity. When the melting point is restored to the glass transition temperature, the rearrangement of molecules has a contraction force.

7. Deformation problem: first of all, we need to understand the gate setting, shape and size, which are the key factors, and then the process parameters. The reasons are: (a lot of content, omitted)
(1) uneven molecular orientation
(2) improper cooling
(3) unreasonable mold gating system
(4) unreasonable mold demoulding and exhaust system design
(5) improper process operation
Troubleshooting:
(1) too high mold temperature or insufficient cooling. The mold temperature should be reced or the cooling time should be extended. For the slender plastic parts, the cooling method can be adopted after the mold is fixed
(2) uneven cooling. The cooling system of mould should be improved to ensure uniform cooling of plastic parts< (3) the gate selection is unreasonable. The reasonable gate form should be selected according to the specific situation. In general, multipoint gate can be used
(4) the die is eccentric. It should be checked and corrected< Analysis and elimination methods of cavitation defects:
(1) improper control of molding conditions
(2) mold defects
(3) raw materials do not meet the use requirements

8. In the process of injection molding, the uneven cooling and excessive resial packing pressure will proce internal stress, which is formed in certain environmental conditions