Plastic Mold Tryout

Published on October 2017 | Categories: Documents | Downloads: 18 | Comments: 0 | Views: 353
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Why need plastic mold tryout before production

Step 2. Set the temperature of the mold.Similarly, the initial mold temperature settings must also refer to the recommended values from the material supplier.Note that the mold temperature here refers to the temperature of the cavity surface, rather than the displayed temperature of the mold temperature controller .In many cases, due to environmental , improper

selection

of

the

mold

temperature

controllers and other reasons, the temperature and the temperature of the mold cavity surface are not consistent. Therefore, before the formal tryout, the improper design of the mold often cause the final

cavity surface temperature must be measured and

product with some defects,especially for injection

recorded. Meanwhile, the different mold cavity

molding part for it need more precise size than blowing

position should also be measured, to verify the

molding and rotational molding often. So, before the

balance temperature at various points, and record

plastic mold modification, usually it need conduct a tryout

the corresponding results, provide to optimize the

or evaluation for optimization of mold design and process

reference data.

parameters, so as to avoid unnecessary errors, achieve



Step

3.

Based

on

experience,

the

initial

good products, then meet the quality requirements of mass

plasticizing setting, injection pressure limit, injection

production.

speed, cooling time , screw speed and other parameters

The steps of tryout of plastic mold

be

figured,

and

make

its

appropriate optimization later.

 

could

Step 4. Have a test to identify the switching point.

Step 1. Set the barrel temperature.It should be

Which is a stage point from the injection stage to the

noted that the initial temperature of the barrel must

packing stage, it may be the screw position, the

be set in accordance with the plastic material

filling time and filling pressure. This is one of the

suppliers’ recommendation. This is because different

most essential and basic parameters of the injection

manufacturers produce different brands of the

molding process . under the actual test, the following

plastic material which may have quite a big

points should be followed:(1) holding pressure and

difference, and those material suppliers often have a

holding time is usually set to zero for the first trial;(2)

very indepth study and understanding of their

products filling depends on the wall thickness of

products.Users can have basic settings according to

products and structural design of the mold;(3) for the

their

the

injection speed would effect the position of switching

appropriate modification on the real production.In

position, so after each change of the injection

addition, it also need use the detector to measure

speed , we must reconfirm switching points, the

the actual temperature of the melt. Because we tend

material flow path in the mold cavity could be found,

to

thereby

recommendations,

set

the

barrel

and

then

temperature

have

effected

by

trapped

air

area

could

be

easily

environmental temperature, type and location of the

determined,then decide how to improve to vent the

depth of the temperature sensors,which does not

mold.

guarantee 100% consistent with the real melt



Step 5. Find the limit of the injection pressure. In

temperature. Sometimes, because of the presence

this process, it should be noted the injection

of oil or other factors, the temperature difference

pressure and injection speed is related.For hydraulic

between the actual temperature of the melt and the

systems, injection pressure and injection speed are

barrel is very large.

interrelated. Therefore, these two parameters can

www.plasticmoulds.net not be simultaneously set best to meet the required conditions.Injection pressure on the screen is a limit of the actual injection pressure, and therefore, injection pressure limit should be set larger than the actual value of the injection pressure . If the injection pressure is set too low, the actual injection pressure is close to or exceeds the limit value of the injection pressure, which would affect the injection molding cycle time.



Step 6. Optimizing the injection speed. Injection speed referred to the speed which could meet the shortest filling time demand and the lowest filling pressure demand.the following points should be noted:(1) Most of the product surface defects, especially defects near the gate, are caused due to the injection speed.(2) multistage injection can not be adopted only when the one time shot couldn’t meet the needs of the process , especially in mold test stage.(3) In the good mold condition, correct switching point setting and the enough injection speed , there is no direct relationship between the injection speed and product flash.



Step 7. Optimization of holding time.holding time is time of the gate solidifying. In general, the holding time may be determined by weighing the products to obtain different time, and optimized holding time is when the products get its max weight.



Step 8. Optimizing other parameters, such as holding pressure and clamping force and so on.Finally, it should be emphasized that the purpose of plastic mold trial is to optimize the tooling and injection processes to meet the requirements of mass production, rather than just a good test sample.

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