Tim Bruening - Fab Academy 2016

Week #17 - Applications and Implications

In the seventeenth week we were tasked to propose a final project that integrates many of the topics covered in FAB Academy.

What are the different processes used to make the final project?

• Using project management techniques to decide on a project and manage the tasks needed to produce it.
  
• 2D CAD for original designs and vector files for laser and Shopbot.
  
• 3D CAD for 3D printing and mold making.
  
• Eagle CAD for circuit and board designs.
• Computer controlled cutting for acrylic roller frames.
• Electronic PCB board manufacture. Design, machine, solder and program.
• 3D printing for rollers and mold.
  
• Computer controlled machining for wood frame pieces.
  
• Mechanical and Machine design for design and integration of all components.
  
• Input devices for hall effect sensor.
• Output devices for control of vacuum pump.
• Networking and communications between the ATTiny45, the hall effect sensor and the vacuum pump control.
• Invention, intellectual property and income to help decide what to protect for the future.
• Project development puts it all together.

Here is a list of questions we need to answer as we finish our projects.

• What will it do?
  
• Who has done what beforehand?
  
• What materials and components will be required?  (BOM)
  
• Where will the materials come from?  (BOM)
• How much will the materials cost?  (BOM)
• What parts and systems will be made?  (BOM)
• What processes will be used?
• What tasks need to be completed?
• What questions need to be answered?
• What is the schedule to finish the project?
• How will it be evaluated?
• Were any problems encountered?

What will it do?

A vacuum forming (thermoforming) machine heats a sheet of plastic until it is pliable.  Once pliable a vacuum is used to evacuate

the air between the plastic sheet and th mold causing atmospheric pressure to push down on the sheet forming an exact contour of the mold. 

 I will use the vacuum former in Grandpa's FABlab to make candy molds.

Who has done what beforehand?

Vacuum forming has been around for many years.  I operated one in 1969 to make formed trays to package N-gage train sets.  

Today, almost anything you see in a store that is packaged in a clear plastic container is vacuum formed.

Bill of materials questions

• What materials and components will be required?
• Where will the materials come from?
• How much will the materials cost?
• What parts and systems will be made?
• What processes will be used?

Here is an image of the total bill of materials (BOM).

Here is an image of the BOM for the Hall effect sensor board.

Here is an image of the BOM for the ATTiny44 board.

Here is an image of the BOM for the Heat Box.

Here is an image of the BOM for the Vacuum Box.

What tasks need to be completed?  (as of 5/25/16)

I currently have both the heat box and the vacuum box completed.  I need to finish the design, machining, populating and programming of the two PCB boards needed for the project.  

One board is the control with the ATtiny44 micro controller.  It will e used to control the circuits and provide a timer for the process.  the other board will contain the Hall effect sensor.  

It will be a separate board for easier placement near the magnet.  It will also keep the main control board away from the heat.  I also need to integrate all of the electrical components

into one system.  I will use a double electrical outlet on the hot side of the wires going to the vacuum pump.  the neutral of cold wire will go directly to the pump.  

The hot wire will come from the DC/AC relay controlled by the ATtiny44.

What questions need to be answered?

What material and thickness should I use to make the final part?

I decided to use 0.020" thick polyethylene terephth late (PETG) because it is a food safe material.

How long do I need to preheat the Heat Box?

I found out that it takes about 10 minutes to reach a temperature of 540 degrees F

I used an infrared thermometer to detect the temperature of the heating element.

How long of a delay do I need to program into the ATtiny44 program.

Through experimentation I determined that it took 75 seconds for the sheet to become pliable.

How do I attach the components to the base?

The heat box is allowed to roll on its own. Wood screws are used for everything else.

What is the schedule to finish the project?

Finish design of PCBs.

Machine PCBs.

Populate PCBs.

Program control PCB.

Determine heat and cycle times.

Integrate all components into one system.

How will it be evaluated?

The systems will be evaluated by making a vacuum formed part.

Were any problems encountered?

I do not recall any major problems coming up with final schedules and designs.

After 17 weeks I think I am improving in my ability to create PCBs.