A Case Of The Clap.....Trap

As 2013 continues, I have begun to work on my own 3D designs and am trying to build my skills with the cnc.  I believe it's easy to get locked into doing things a particular way, and not pushing to do more complex things.  I'm still in the process of tackling 3D modeling, so I thought I'd rather focus on the carving.  There are some great, reasonably priced models at GrabCad.

One hold-up for many of us is budget.  Materials are expensive, and it's scary to invest money in a risky experiment or a learning experience that doesn't work out.  It's one of the reasons I don't mind learning by carving low density foam.  Foam is not a great choice for things you want to keep around, unless it's a dense foam like HDU.  Once I'm confident about a process I move on to excellent materials for my samples and clients.

I've noticed the white foam at stores like Menard's (1 and 2" thick).  It's even less expensive than the pink and blue insulation foam found there.  A 4' x 8' sheet that's 2" thick is under 12 dollars.  That's not a bad cost for having that much material to try things out.

I picked up a sheet last week because I knew I wanted to try carving something that would require a large sheet.  I wanted to see what the amount of time to carve would be, and once again experiment.  In particular, I have been reading up on cnc ramping values.  The material being used impacts what you can do and shouldn't do, and I'm building an understanding of how to tweak my machine to run the best it can while not sacrificing speed.  Experimentation is really the only way I trust.

So- I thought another small, easy to dissect robot would be fun.  This little guy is called Clap Trap.

  He's a robot from the fantastic Borderlands video games by GearBox.  They've been suffering under a poorly received Aliens: Colonial Marines game.  I haven't played the game, but know how hard it can be to have something you've done be received poorly.  Deserved or not, the last week or so has been hard on them.  I'd rather spend time on something fun. ClapTrap is exactly that.

The 3D model comes from a man named Mesut Akçay via GrabCAD. At 5$ is was a bargain.

I spent some time working out how to break him into pieces (I will soon do a full explanation of how I do this) and then to set up my carving...while playing with some speed values.

I wanted to do a little test on the foam, so I started off by working on the wheel.  These two halves represent the outer portions.  I decided that to give him a little strength when he's put together, I'd make the center portions out of Azek pvc.

Once I got the pvc cut, I glued them together and then started work on priming and coating them to be a little tougher.  I was really impressed with how well the foam carved.  I had little expectation, and it came out well.  The speed wasn't bad, but I had additional modifications to try on the big carve.

Next up was the big carve.  I seperated the model in to multiple components  and set up the 4' x 8' sheet on the Bot.  The expected time to carve it all was about 15 hours.  With additional modifications, the actual carve turned out to be about 6 1/2 hours.

 Additionally, I decided to experiment with something else. I have been trying out a 2 stage approach where I carve in 2 stages. The first is an overall carve with a larger bit (faster) and then specific areas are carved for the second run..at a higher resolution with a smaller bit.  I picked out key areas and only recarved those. That took less then 2 hours.

Next, I glued all the pieces together.

Make no mistake, the foam has some drawbacks other than being flimsy.  If you want a decent finish, there will be work.  I've cleaned the body up, and have spent a little time this morning getting it smooth and a harder finish on it as well.

Now...how many minutes before someone points out that the wheel is upside down?

Next?  Continued work on the body and work on the big "lens".

Stay Tuned!