Week 7 Minor Project

Objective

Obtain the result of a fill+pack+warp analysis on the model and from the result identify the main contributing factor for the warpage on the model.

procedure

following is the process to obtain the results:

• Create model with having specification given below:
  1. Base diameter = 100 mm
  2. Top diameter = 160 mm
  3. Height = 50 mm
  4. Thickness = 5 mm

• Choose to dual domain mesh with having global edge length of 2.5mm

• Gating system

• There are three gating system:Gate
• Runner
• Sprue

• Gate specifications:

Number of beams	20
Cross section	Rectangle
shape	Tapered by end dimension
Cross sectional dimensions	Start width 10mm Start height 10mm End width 20mm End height 5mm

• Runner specifications:

Number of beams	50
Cross section	circular
shape	Non tapered
Cross sectional diameter	10mm

• Sprue specifications:

Number of beams	45
Cross section	Circular
Shape	Tapered by end diameter
Cross sectional dimensions	Start diameter 7mm End diameter 10mm

Gating system shown below:

• Set analysis sequence to ‘fill+pack+warp’

• Select material as ‘Lexan 940: SABIC Innovative Plastic US, LLC’.

Details of selected materials are:

Details	Sub details
Manufacturer	SABIC Innovative Plastic US, LLC
Trade name	Lexan 940
Family name	POLYCARBONATE (PC)
Material structure	Amorphous

• Perform process setting wizard:

Details of process setting wizard are:

Details	Sub details
Mold surface temperature	82°C
Melt temperature	301°C
Filling control	Injection tome of 1.2s
Velocity/pressure switch over	By %filled at 95%
Pack/holding control	Packing pressure vs time: durations Packing pressure 0.2 25 2 20 2 15 1 10
Cooling time	Automatic
Number of laminae	14

• Start analysis and after completion of analysis, there are two analysis found i.e. flow and warp.

Flow result:

Fill time	1.302 sec Animation =https://www.youtube.com/watch?v=sxEDLfcR9aU
Pressure at v/p switch over	41.49 mpa
Temperature at flow front	302.8°c
Bulk temperature	40.98 sec
Shear rate, bulk time	1.303 sec
Volumetric shrinkage at ejection	8.176 %
Time to reach ejection temperature	74.98 sec
Frozen layer fraction time	40.98 sec
Average velocity time	40.98 sec
Bulk temperature at end of fill	311.0°c
Flow rate, beam time	40.98 sec
Frozen layer fraction at end of fill	0.0779
Pressure time	40.98 sec
Pressure at end of fill	35.19 mpa
Shear stress at wall	40.98 sec
Sink mark, index	5.754 %
Volumetric shrinkage time	40.98 sec
Flow front speed	421 cm/sec
Cavity weight time	40.98 sec
Maximum injection pressure (at 1.22 sec)	41.4857 mpa

Warpage result:

Deflection	(Min – max) range in mm
All effect	0.3319 – 1.023
Differential cooling	0.0000 – 9.E-07
Differential shrinkage	0.3319 – 1.023
Orientation effect	0.0000 – 5.E-09

• Causes of warpage

There are three different causes for the warpage are:

1. Differential shrinkage
2. Differential cooling
3. Orientation effects

• outputs after my own observation are:

1. The model should be of uniform thickness.
2. Temperature should be maintained uniform throughout the thickness.
3. Selection of isolate warpage tends to give a greater number of warpage results like differential shrinkage, differential cooling and orientation effects and also along the x, y and z directions.
4. Selection of dual domain mesh tends to give quick result and lesser accuracy as compare to 3D mesh.

Learning outcomes:

Following are the things that I have learned in this challenge are:

• Warpage is defined as the change of shape from its original shape due to factors like differential cooling, differential shrinkage and orientation effects.
• The shape of model should be like that should create minimum warpage. i.e. wall thickness should be uniform
• Gating system should be properly designed in order to avoid warpage.
• Proper material selection in order to avoid warpage. Material should be selected according to application of the product.
• Interpretation of flow and warpage results.

Conclusion:

The challenge was an amazing for me as there was lot of things to learn like warpage, fill+pack+warp analysis, design of proper gating system, selection of proper material that suits the product according to its application and also learned various interpretation of results. The credit goes to skill lync for helping me in completing this challenge. And also providing me the amazing platform to enhance the skill.

Thanks