Report 3 Updates

1. REDESIGN

Justification and discussion of the process optimization and possible mold redesign. Include what problems occurred if any and give reasoning behind the parameter adjustments or mold modifications that were made that improved the condition.

1. Housing

The team that redesigned the housing consists of Tyler, Andrea and Cheetiri.

The housing had to be redesigned because we ran into many issues when the team injection molded the part. Even when parameters were changed in the injection-molding machine, the housing still had issues. The problems the part had were:

•    Wedging on the backside, which should be very flat to be able to be attached to the other housing. This was fixed my decreasing the thickness of the part as much as possible. 

•    O-ring groove was too small after shrinkage. The groove diameter was increased to 2% more than the O-ring to account for shrinkage.

•    The diameter for the snap fit was too big. The diameter was decreased but accounted for shrinkage of 1.65%.

•    The lip on the outer rim of the housing was removed completely since it served no purpose.

•    There was some flashing happening at the snap fit location, so the thickness was decreased.

Again, just the thickness of the part created many issues having shrinkage of 2-3%. The agitator had no issues since it fits perfectly with the thermoform bubble.

The ejector pins level was changed from level 6 to level 4. Also, the thickness might have to be increased a little, but that can be easily lathe. Nothing else would change.

B. Inner Ring

C. Bubble

D. Outer Ring

-          inner ring dimensions

-          outer ring (snap fit)

-          housing (snap fit)

-          housing (thick part, shrinkage, burning, warping)

2. DIMENSIONED DRAWING

A fully dimensioned drawing of the part. In the event of a redesign, a fully dimensioned revised drawing showing the new design specification as well as a fully dimensioned revised drawing of the mold including matching revision levels.

3. MASTERCAM

In the event of a redesign. A new set of Mastercam geometry files and associated G-code programs for the altered mold. Include the matching updated revision level in both file names as a suffix in the file names. Please do not print the code. The updated G-code files, (xxx.txt for mill), (xxx.nc for lathe) must be available for uploading to the appropriate machine at your machining appointment. The updated Mastercam geometry files must be available for toolpath review at your appointment.

The lathe and mill work for the housing molds are done. We just need to test it with the injection-molding machine. The files are uploaded in the course locker and were used during machining of the molds.

Lathe:

HOUSING_AGITATOR_CAVITY_REV4.NC

HOUSING_AGITATOR_CORE_REV4.NC

Mill:

HOUSING_AGITATOR_CORE_EJECTORPINS_REV4.txt

HOUSING_AGITATOR_CAVITY_RUNNER_REV4.txt

4. GANTT CHART

Update the posted Gantt chart. (Your team’s component(s) only).

https://docs.google.com/spreadsheet/ccc?key=0AhEy-axAED8UdHpickJiS1l6cV9RNGd2aWFfRTNCNkE#gid=0vv

5. OPTIMIZATION PARAMETERS

Post your component’s set-up sheet showing all the optimized parameter settings that will be used to run production for the component. Include the ejector-pin length, and shim thickness used for the mold. Make sure you have a copy of the optimized parameters when you submit a copy to us. You will need these to know these parameters when you are in the shop.

A. TOP RING (snap fit) w/ numbers

Injection hold pressure profile:

300	350	400	450	500
450	400	350	300	249

Injection hold time = 8.0 s

Cooling time = 25.0 s

Set screw feed stroke = 1.2 in.

Ejector pin length: 5.647 in. (#8)

Total shim thickness: no shim

Total cycle time: 33 s

B. INNER RING

Injection hold pressure profile:

Injection hold time = ___ s

Cooling time = ___ s

Set screw feed stroke = ___ in.

Ejector pin length: ___ in. (#___)

Total shim thickness: ___

Total cycle time: ___ s

C. HOUSING

Due to late redesigning of the part and no space in the injection-molding machine, the new housing has not been tested. We plan to test it on Wednesday or Thursday. We have made an appointment already, but we do understand that this should have prepared better. Due to the new thickness of the part, we expect to use the normal parameters set on the machine with a higher injection speed. The cooling time will probably be set to 25 seconds to reduce shrinkage.

D. BUBBLE

Not sure what the parameters are here…