MOULD MANUFACTURING CHECK LIST:

 

MOULD MANUFACTURING CHECK LIST:

Are all parts secured properly & tightly?

Is the cavity polished in the direction of the ejection?

Is any negative taper in the inserts?

Is the ejection system are actuation proper?

Is the die set actuation proper?

Is the locating ring suit the machine hole?

Is the cooling circuit proper with any leakage?

Is the tie bar tightened properly?

Are the proper lifting holes are provided?

 

When the tool is subjected to the actual working conditions, the performance is noted and if there are any defects they will be reworked if necessary.

 

TOOL CLAMPING:

There are two methods of securing the tool to the press platens namely direct bolting & clipping .the first system employs bolts which pass through holes into the back plate and threaded holes is pulled by the bolt and later engaged a conveniently positioned hole in the platens, with one end on the packing and other on the tool back plate.

 

 

ESTIMATING CYCLE:

For estimating cycle the important point to be necessary are: -

MOULD

Mould opening -300mm

Ejector stroke -45mm

Shot weight –

 

PRESSURE

Clamping pressur -150Ton

Injection pressur -108Bar

Holding pressur -38Bar

Ejector pressur -30Bar

Back pressur -5Bar

 

SPEED

Injection speed -60rpm

Screw speed -20rpm

 

TIME

Dosing time -2.79Sec

Injection time -0.49Sec

Holding time -5.0Sec

Cooling time -40Sec

Mould opening time  -4.05Sec

Mould closing time -3.07Sec

Cycle time -78Sec

 

TEMPERATURE

Nozzle temp -295Deg.c

Feed temp -60Deg.c

SCREW TYPE INJECTION MOULDING MACHINE:

This type of the machine consists of the screw, rotating in the hot barrel capable of delivering continuos melt of the plastic material through the nozzle can be had because of the shearing action and the material flowing in different patterns there is homogeits in the melt.

 

MOULDING PARAMETERS:

Mould height          :346mm

Mould size              :396X296X346mm

Shot capacity of PP:3.48 ounces

Plasticizing capacity of LDPE:15.29kg/hour

Shot weight             :75 gms approx.

 

TRY OUT

Tool is loaded onto the injection moulding machine all necessary parameters are set in the machine the material is poured into screw cylinder through the hopper the mould is pre heated to the temperature of 120-125deg for 3hrs before injecting the material the tool is closed & the material is injected through the machine nozzle after noting the cycle time the component is ejected out in first some shots the component was not filled properly since there are some in profiles so effective heating and increased injection pressure gives us the fully filled component.

 

After taking care of all the defects in first try out our second try out was successful.

 

 

CYCLE TIME

          This is the tool time taken for the  complete cycle for the production of the one component .it consists of the following stages

1)    Closing of the mould: The releasing agent is sprayed on the core and cavity  before closing .the clamping force of 250 tonnes is applied to close the mould on the projected area. Clamping force is also referred to as the locking force. After the mould is closed cam pin are actuated which enable the side core to  but the core inserts.

2)    Injection: The injection ram comes forward along with the hot plasticise material and then injected under pressure by screw which acts like a plunger the hot material is injected through the nozzle into the closed mould cavity via sprue bush runners & gates. The plunger provides necessary pressure to inject the plasticised material.

3)    Cooling: The cold water or oil is circulated through the cooling channels to cool the core and cavity and maintain mould working temperature .After injection the mould is held under pressure until the mould piece is cured.

4)    Opening of the mould: First the nozzle is retracted back  and  then the clamping force is released and the mould is opened.

5)    Ejection: As the mould open’s further at first slider are moved back and locked by ball catch, the fixed stopper provided in the machine actuates the ejector system of the mould components are ejected.