MTM Machine and Others:
For the last week or so, I have
been learning about the MTM machine. I found a set of
plastic sitting next to a trashcan that had been mis-routed, but at the
time I wasn't sure how poorly. All of the
pieces are very tight fits, and some holes are offset, so the task has
been to try to put them together, and see if the errors can all be put
in the same direction to get the pieces to work.
So far, it isn't as bad as it sounds -- the pieces were fitting
together and I didn't know how messed up they were.
The main frame is assembled, the tray, and this week I worked on the
head, which seems to have the most problems.
For the most part, the material is
soft enough to mash into the correct positions. The snap
connectors are quite robust, even with large misalignments!
Great work Johnathan!
To raid the junk box, and reduce expense, I am looking at using
found motors, etc. For the positioning I am thinking:
- Use a cable system for positioning similar to an old radio dial.
- Use leadscrews I have laying around.
- Order the expensive leadscrews from McMaster Carr.
- I plan on replacing the head with something more universal to
allow mounting other tooling for other purposes.
I don't have bearings, so those I have put on order this morning.
Videos of Johnathan explaining some stuff to the group are here:
(They are currently uncompressed... so they may be big!)
And photos of me beating on plastic:
Final Project Thoughts:
My initial interests are in low cost rapid prototyping
techniques, and modular machine
building/automation. Neil expressed that I
should have a concrete end goal/design in mind, instead of a platform
to build machines on, and a bunch of building blocks.
Three concrete applications that come to mind:
1. Miniature electronics assembly machine:
- A small pick and place machine
- Possibly adding solder dispensing, component placement, and board
- Optionally, extend it to mill the board also.
2. Object copier
- Build out the rotary 3D scanner. Add a printing or carving
machine, or additive machine to it (i.e. use MTM snap or another)
3. Machinable Wax Recycling Machining Center
- We milled the wax, which can supposedly be
reused. Add an attachment to a Modella class mill to
catch the grindings, and form a new block in which to mill.
- Alternatively instead of milling, look at an additive approach
that uses recycled material.
Near Term Approach:
Many of the above use the same underlying
Bask in success and watch it make things. :)
- Build/debug motor drivers that can be used for positioning.
- Integrate some motors into a mechanical x-y-z type assembly.
- Write code to send cad or other pc source to table.
- Final decision on application.
- Order any necessary parts.
- Build end effector(s) depending on final application or
supporting materials for end application.
- Build controller for end effectors/tooling
- Write PC code to send data to the device.
The focus in the above is on the high level
application. For that reason I may combine some
pre-assembled slides, or other mechanisms to compress development time
for this initial prototype.
Video player to try when I get a chance: http://www.longtailvideo.com/players