In the nineteenth week we were tasked to complete our final projects.
Here is a list of questions as I see them for the nineteenth
week.
The heat box and the vacuum box are completed. The hall effect PCB and the ATTiny44 PCB are machined and populated.
Tasks remaining include programming the PCBs and integrating the components into one machine and finishing my unfinished web pages for earlier weeks.
I manually connected the vacuum pump to the vacuum box. I also plugged in the heatbox to warm it up.
I then put the model in the vacuum box and installed a 0.020" thick sheet of PETG for a test. I watched to see when the material began to sag due to the heat.
I then turned on the vacuum pump to see how it worked. I ran multiple tests with different models and timed how long it would take for the sheets to become pliable.
After many tests I determined that 75 seconds was the correct time for preheating the plastic sheet. This will be the delay used in the final program.
My use of a repair element for an electric stove worked just fine. Also, sealing a plywood box to use for a vacuum was surprisingly easy.
Using a dimmer switch to control the burner did not work well. I found that I could get a higher temperature output if I eliminated the dimmer switch altogether.
I originally thought that I would have too much heat and I would have to lower the temperature.
Also, I did not have the time to put the heating box on rollers.
How will everything work after integration into one machine? I will leave at least three days for testing and debugging the final machine.
In the next week I will attach the components to a plywood base. Next I will program the PCBs and make sure everything is in working order.
Since I only had one week before my scheduled presentation I decided to concentrate on the final project and leave the unfinished web pages until later.
I should have plenty of time to finish them after my presentation.
I figure that it will take most of my week to program the ATTiny44, test the program manually, connect the other comonents and then test the final machine.
I allowed one day for programming, one day for testing the program, two days for connecting everything together and at least one day for final testing.
I plan on using the last two days to prepare my presentation slide and video. This will also give me some time in case something does not go quite right.
I know the concept of the machine works. I only need to put everything together. I have a much more detailed description in my project report.
I learned how to manage a project with the focus on building a machine. The following questions all had to be answered along the way.
What project should I tackle?
I decided to go along with FAB 2.0 and make a machine for Grandpa's FABlab. I have a laser, vinyl cutter and 3D printer so a vacuum former seemed to be a good idea.
I originally thought that It would have an elevated heating element that would lower down to the part when ready. It turns out that idea was a little too much for the time frame I had to work with.
I decided to make a manually operated machine with automated timing for the vacuum to turn on. The hard part of using a small vacuum former is how long does it need to heat the plastic sheet.
Do I have the skills?
I have quite a few skills already but needed help in managing my time. Neil always tells us to look at what is the priority and not waste time on the wrong tasks.
Many times I had to get off my train of thought and work on the most important task at hand. I learned how to budget and prioritize my time better.
There were a few weeks during the semester that I was ready to hang it up. I used Neil's method of looking at what is the most important thing to do first.
My background as an engineer kept trying to steer me into doing things in order. Week #1, week #2, .... I scheduled my presentation for June 20 and had to be done by then. I could always finish up my weekly web pages later.
I would not have finished my project in time for my presentation if I would have done the last few assignments first.
I also learned how to design, machine, populate and program electronic circuity. Electronics is the topic I improved in the most.
Do I have the time to get it done?
As I mentioned earlier I had to learn better time management. I also had to limit how much of my original idea I had time to make.
20 weeks is not all that long when you are learning all the topics covered in FAB Academy along with designing and building your project.
I plan on adding rails for the heating box to run on. It will help in keeping the components aligned. I allowed for the addition of rails.
I will need to alter the height of the heating box. I just need to take it apart and shorten the two sides.
The only other plans I have now is to assemble the laser cabinet I made in week six and finish getting Grandpa's FABlab setup.