Final Design

Cutting

There are two cutters(top cutter and bottom cutter) in this deflashing machine. Both are pneumatic driven and the cutters were made of stainless steel which is much stronger than aluminum. The top cutter consists of a sharp blade, two customized block cutter and a mounting plate that connects the prior parts together. Due to the long diameter of the dome flash, the top cutter is powered by a pneumatic actuator with a stroke length of roughly 46cm. The bottom cutter was made of a customized block cutter(See Fig.) and was powered by a 15cm of stroke pneumatic actuator. 

Framing

To ensure the necessary stress, the 5cm by 5cm aluminum t-slot anodized extrusions were chosen to build the main frame of the de-flasher. After doing the pressure analysis on the frame based on the given elastic aluminum extrusions, it was concluded that this type of frames could easily handle the total weight of the pneumatic actuators and the attached metal parts. The entire frame was screwed tightly with aluminum brackets and corner connections to ensure stability. 

        CAD file of the Aluminum Frame                                                   Aluminum extrusions cut to different length

Safety

The protection mesh would prevent any potential possibility of any operator reaching the machine while it is operating. One can only access the machine from the door side where a switch would shut all the power off if the door is open(the demonstration is below). During the process of locating/removing containers, all the pneumatic driven parts would stay at their home position with the power being shut. There is also an emergency stop button which allows all the actuators go back to their home positions once pushed(the demonstration is below). The team also built in an extra safety mechanism that stops the cutters from going down if the container is not located correctly.

After the emergency button was pushed:

After the door was opened during operation:

Summary of the Performance

Multiple tests on the flow speed and the air pressure for each pneumatic actuator were done to find the ideal values. The team uses the maximum air pressure available(551.6kPa) for the top and the bottom cutters to optimize their cutting performances. 206.8kPa was chosen for the clamp due to the possibilities of deforming the container itself during the clamping. Appropriate speed for each motion was also determined to fulfill the safety standards. The table below shows the detailed information of the speed and air pressure for each pneumatic:

Below is the demonstration of the deflashing machine with program.

Below is the demonstration with an actual container.

As you can see in the video, the top cutter assembly was stuck in the middle of the trimming and was not able to finish the deflashing as expected. Possible reasons include insufficient air pressure and low temperature of the flash. From the figure below, however, it can be seen that the cutting edge aligned with the dome perfectly without damaging the container itself. 

During the demonstration, the team was trying to heat the container with a low-efficiency heat gun which failed to heat up the container uniformly to the actual temperature of which coming out of the blow molds. Higher temperature will make the flash significantly easier for penetration. The highest air pressure at the factory is also 827.37 which is much higher than that at the machine shop. Higher air pressure will also increase the cutting pressure.

• • Operation time: less than 60 seconds 

  • Trimming result: majority of the flash came off from the container except for the dome

  • Trimmed surface: smooth for the neck and the bottom

  • Safety concern: door switch and the mesh will prevent most of the potential accidents 

  • Ease to use: press one button and go 

  • Overheating: not a concern considering the resting time