CarBEN Model -- 1/24th scale model and 3D computer model for EV

[NeilBlanchard]

I'm using Creative Commons license for CarBEN EV5 now:

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[NeilBlanchard]

I've got the PhlatPrinter 3 working properly again! The driver board cannot handle the 2.5A stepper motor I tried, and this blew the channel. And there seems to be a bug in the plugin that generates the G-code -- when I used tabs (to hold the cut pieces in place in the sheet) and 2 depth passes, the g-code was messed up. When I do not use tabs, all is well.

Woohoo!

I even got it to cut through all but 1/16" and I know that I need a longer cutting bit that has a little more than 2" of cutting edge, and the gantry needs a modification to get a little more height range, so the longer bit doesn't skim the top surface.

[JethroBodine]

Sounds good, Neil! When's the new bit(s) going to arrive?

[NeilBlanchard]

I called the local company and asked for a quote -- their minimum order is 5 and that sounds about right to cut ~45 sheets. They can be sharpened, too. I asked for a ball end so I can do 3D shaping with the PhlatPrinter 3, since it can do this. The nose and the tail may be a lot easier to do if I use it to shape the foam.

The bits are likely to be ~$100 each or maybe more. I was hoping for ~$50 each, but I still think it will be worthwhile getting them.

We had this freaky snow storm and they were still out of power on all but one leg of the feed, so this will slow down their response.

[CFECO]

Neil, What is the size of those bits, $100/each seems steep to me. Are they carbide, cobalt, or? Shank dia, length, flute count, dia, length.

[NeilBlanchard]

The bits will be 4-5mm in diameter, and be 70-77mm long and have ~54mm of cutting edge. They will be carbide and have either up-spiral flutes (probably 2) like this:



or have a triangular knurling kinda' like this:



We'll see how much the actual quote is for.

[NeilBlanchard]

Well, I need to make do with the 2.25" long up-spiral bits I have -- the company I wanted to make the longer bits cannot get 4mm carbide stock long enough to make them.

Oh well, I'll chuck up the sharp one I have and see how the next sheet goes...

[CFECO]

Are theses from a Dremel tool or Rotozip? Does the motor have a collet, and if so can it accept non metric bits?

[NeilBlanchard]

Some Rotozip bits are longer than any of the Dremel bits at Lowes. The tool is a Chicago cable driven rotary tool with a small conventional chuck -- it cannot open wide enough for a 3/16" drill.

Flexible Shaft Grinder and Carver

I'm going to use the bits I have -- I noticed after cutting the sheet that the gantry wingnuts had loosened and this could explain some of the drift I was seeing. I'm learning what to stay on top of...

[NeilBlanchard]

I've been beavering away on the DataCAD drawing for CarBEN EV5, and these are the 42 sections forward of the high point on the roof; starting at the very front of the nose:



The front sections are ~1" thick because the transition is rapid, and the "stacked" sections are where I need to use a shallower depth to stop a feature. The majority of them will be 1 15/16" thick though -- there are about 85 of these, so this represents less than half -- and they are not done yet. There are five and a half sheets laid out -- I will know how many it will take to do the whole chassis when I finish this!

I will be using 1" thick foam sheets and just cutting two of each. This will let me use the bits I have and the machine will handle them a lot better without any farther futzing with the high current driver board and X-axis stepper motor.