Bottom cover & Top cover_hard part

2020-06-18

Moldflow Analysis Report

Mold Number：16033

Prepared by：Leo Tang

Date Prepared：July 5th 2019

Version：Rev.1

Project Summary

Analysis Purpose	Validate potential problem after the part and mold design Check the fill balance pattern, weld line, air traps, and predict the needed clamp force and injection pressure, warpage.
Input Model Description	The runner system is simulated as the mold design.
Result Required	Filling result Warpage result
Actual of cavities	1+1
Number of cavity analysis	1+1
Part Material	PC+ABS
Type of analyses	Flow + Warp

Material Data

■ The material datas are from supplier is in moldflow database and shown in the pictures below

Material Property
PC+ABS (Bayblend FR1514 from Covestro)		Melt Temperature Range (℃)	250~280
Solid Density (g/cm3)	1.17	Mold Temperature Range (℃)	60~80
Maximum Shear Rate (1/s)	50000	Ejection Temperature (℃)	135
Maximum Shear Stress (MPa)	0.4	Absolute Maximum Melt Temperature (℃)	320
MFR (g/10min) ( ℃/ Kg)	/	Recommended Melt Temperature (℃)	260
Filler	Unfilled	Recommended Mold Temperature (℃)	70

Rheology:

PVT properties:

Part、Tool、Setup

Part Details and Tool Description
Part Name	Bottom cover & Top cover_hard part
CAD File / Version/ Date	16033_nrgkick_dsgn_asm_190627 /stp
Part Volume	207 (1*1) cm^3
Nominal Wall Thickness	No uniform
Tool Description	1+1 Cavities
Injection machine Tonnage	/

Process Setup
Material	PC+ABS (Bayblend FR1514 from Covestro)
Injection time	2.5 s
Material temp	260 [deg.c]
Mold temp	70 [deg.c]
Velocity/Pressure Transfer (% volume)	98 %
Packing Pressure/Time	80% filling pressure /8 s, 60% filling pressure /4 s
Project Area	367 (1+1 ) cm^2

Wall thickness

This above plot used different color to show the thickness of this part.

We can see that: the average thickness of this part isn’t uniform.

Total part weight = 237 g (1+1 ) , the cold runners weight = 34 g

This above plot used different color to show the thickness of this part.

We can see that: the average thickness of this part isn’t uniform.

Total part weight = 237 g (1+1 ) , the cold runners weight = 34 g

Gate Location and size

■ The mold is the cold runner and point gate.

■ The runner layout was based on the 3D drawing.

Fill time (Animate & Contour)

Pressure at the V/P switchover

Injection pressure

Clamp Force

Weld lines

Air Traps

Time to freeze

Volumetric shrinkage at ejection

Deflection

Conclusions and suggestions

Fill result – Fill animate-1

Fill result – Fill animate-2

Fill result – Filling Contour

The area with dense lines in the above picture represents the area with lower flow velocity; and the area with sparse lines represents the area with higher flow velocity.

Pressure at V/P switchover

Above figure shows the pressure distribution through the flow path inside the mold, at the V/P switchover of the filling phase.

Injection pressure

The maximum value is 88.8 Mpa, Injection pressure specified at Packing is 71 Mpa
The filling pressure are within moldflow recommend value which can acceptable.

Clamp force

The maximum clamp force is 216.6 Tons.

Weld lines locations-1

The weld lines is visible, adding the vent at the weld lines position.
Above figure shows the location of weld-line on the part.
The weld lines form less than 75 degree of the two melt were expected have a bad quality.

Weld lines locations-2

LThe weld lines is visible, adding the vent at the weld lines position.
Above figure shows the location of weld-line on the part.
The weld lines form less than 75 degree of the two melt were expected have a bad quality.

Air trapped area-1

The result shows areas of the cavity that may require additional venting, it should be viewed in combination with the filling pattern result.
Air traps locations mark in red color.
Most of the air trapped appear at the edge of part and the tip of ribs that is easy to vent

Air trapped area-2

The result shows areas of the cavity that may require additional venting, it should be viewed in combination with the filling pattern result.
Air traps locations mark in red color spot.
Most of the air trapped appear at the edge of part and the tip of ribs that is easy to vent.
The serious air traps appear in the red circle.

Time to freeze

The result shows the amount of time taken for all of the elements in the part to freeze to ejection temperature.
The time to reach ejection temperature is about 55 s for 95 % melt volume freezed, the cold runner is about 35 s for 60 % melt volume freezed

Volumetric shrinkage at ejection

Visible sink marks appear on the thick wall and ribs surface.
& The maximum shrinkage at ejection is 5.3 %.The minimum shrinkage at ejection is -0.6 %.

Deflection-All

Note : warpage shape magnified 3X for display purposes. (The undeformed part display transparent)
The maximum shrinkage and deflection value is about 0.96 mm.

X-deflection

Note : warpage shape magnified 3X for display purposes. (The undeformed part display transparent)
The black arrow indicates the shrinkage and deflection moved inward about 0.28 mm.
The red arrow indicates the shrinkage and deflection moved inward about 0.28 mm.

Y-deflection

Note : warpage shape magnified 3X for display purposes. (The undeformed part display transparent)
The black arrow indicates the shrinkage and deflection moved inward about 0.95 mm.
The red arrow indicates the shrinkage and deflection moved inward about 0.89 mm.

Z –deflection

Note : warpage shape magnified 3X for display purposes. (The undeformed part display transparent)
The black arrow indicates the shrinkage and deflection moved downward about 0.24 mm.
The red arrow indicates the shrinkage and deflection moved upward about 0.28 mm.

Conclusions & Suggestions

From the above analysis

■ The cycle time is about: 2.5 (filling) + 50.0 (cooling + packing ) + 16.0 (open & eject) = 68.5 sec

■ This part will not have filling problem due to the pressure are within the moldflow recommend range.

■ Visible weld lines were expected appear at this part. (refer page 15~16)

■ Most of the air trapped appear at the edge of part and the tip of ribs that is easy to vent, some serious air traps appear on the surface. (refer page 17~18)

■ Visible sink mark may appear at the surface of part. (refer page 20)

■ This part have large uneven shrinkage at the X, Y, Z deflection, the different volumetric shrinkage (different wall thickness) result in the defect.

Fill time

2.5 sec
Injection pressure

88.8 Mpa
Volumetric shrinkage

-0.6~5.3 %
Shrinkage and deflection :
X Component

-0.28~0.28 mm
Shrinkage and deflection :
Y Component

-0.95~0.89 mm
Shrinkage and deflection :
Z Component

-0.24~0.28 mm