I will soon have a lot more time to work on getting the higher amperage drive board and X-axis stepper motor set up, and then to start construction of the CarBEN EV5; as the architects I have been working for are running low on work.

 

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.

 

I'm still drafting -- there is a lot more done even than these screen captures show, but this is what I can show you -- these are all the sections at once:



These are a sampling of the sections progressing from the high point on the roof back to the rear doors:



I'm now laying out the 2'x8' foam sheets -- I've finished doing this with the 18th section out of 46 or so.

 

I moved my PhlatPrinter 3 in from the front porch where is was cold, and now that it has been sitting inside for a while, the whole gantry came loose. I think thermal expansion just loosened up the bolts, etc. I'll used some blue LocTite when I reassemble it.

I need to finish the drafting so I know how many sheets of foam to order! ;-) It will be around 100 sheets of the 1" thick XPS. The best place I found has the squared edged sheets for $8.88 each, but it is all the way down in Texas, so I'll have to figure in shipping. The Lowes around here are spotty and they seem to be stopping carrying the blue Dow XPS. A local supplier would be good -- Dow is based around here in Massachusetts, so it would be ironic to buy from Texas.

 

Yes, I will check the cost via my local Lowes store, vs the FRP place in Texas.

 

I have completed ALL the drafting on CarBEN EV5!

Woohoo! There are 49 sheet layouts, and 5 of those are 1" thick, so that means I need a minimum of 93 sheets of foam. I need to export them into SketchUp and process them to then generate the G-code to cut the sheets.

 

I bought 25 sheets of 1" x 2' x 8' Dow XPS foam today! This is 1/4 of what I need to build the whole full size chassis, but it is what I could afford at the moment.

Now I'm diving back into the settings file and I will run the 3 g-code files I have generated so far...

 

Okay, a glitch (or two?) -- about halfway through the run on the first sheet, the Z-height failed to pull up high enough when moving between parts, and then plunged down all the way. This caused the X-axis to get off kilter (since the gantry was dragging on the X rollers).

I restarted the sheet to try again (using the same sheet) and it dropped down too low immediately, this time.

FYI, I upgraded to the latest stable CNC USB Controller program, and it flashed the firmware on the controller board before it started. I'm cutting 1" foam in a single pass, with tabs (which work well to clear the dust and cool the bit).

Any thoughts on a possible cause for this?

 

Here's the video -- it is a noisy thing with both the CNC router and the small shop vacuum running:



You can see when the error occurred at about 10:50 -- I first thought it was a slippage on the Z-axis screw (which you can see me adjusting back upwards after pausing the g-code controller program) but it keeps plunging in. I was hoping that the pieces would be usable, but the resulting X-axis slippage meant that it ran off the back edge of the sheet...

Mark, I'll check the wires on the Z-Axis. I did have to tighten the Z-axis rail bearings (they are still a bit looser than I'd like) and the wires may have been loosened then.

Is there something in the settings file that could limit the downward distance, as well?

And yes, I have thought about Kickstarter -- I'm really not sure how it works fully, yet; so I will look into it.

 

I was pausing the CNC USB Controller program.

I'll check the wire connections and the voltages on the board. What is a good TP1 voltage with the stock (1A) stepper motors?

 

I, too, was not a fan of the z axis pulley setup. I changed mine to two small pulleys. I used the one from the x axis, that was replaced with a alu pulley, to replace the big pulley. Had to change the belt too. I wrote about it in my mod thread. Before the change I had lost steps after the change they were gone and I still get a high enough ipm. 150 with no problem. Maybe lost steps are Neil's problem too?

 

I checked the voltages, and the Z and the Y axes were way too low (under 1v) and I brought them up to ~2.55v. The X axis is my Achilles Heel -- I'm still getting missed steps, but only when the sheet is moving to the back of the machine. I think the belt is too loose.

Remember that I have ball bearings on the idler wheels, so I will tighten it a bit and see if that fixes it.

What voltage is too high? I really have to push the X-axis motor -- maybe I should put a fan blowing on it?

 

I have successfully cut the first 4 sheets for the CarBEN EV5 chassis -- only 89 to go!

WOO HOO!!!

I had to fix two problems: the voltage driving the Z and Y axes was too low, and the drive belt on the X axis stepper motor was loose. And I added back the two side roller rails so that they keep the sheet from shifting side to side. Each piece finished the cut *right* where it started; virtually perfectly...

Today was an amazing day! I've been working for over three years on this project and I finally have something *physical* to show for it!

Here's the video of cutting the second copy of the F23 sheet (it is being processed to remove the hand shake...):



I ran out of space on the camera about a minute before the last part finished, but I'm sure you get the idea...

Now I need to generate more g-code files - and cut hopefully 5 or 6 more sheets tomorrow. Then start gluing...

 

Here's a couple of photos:



I will be lubing everything before I cut anything tomorrow. Especially the router head and shaft -- any hints on what to use? Do the stepper motors need anything? I am running a 120mm fan blowing on the hard-working X-axis motor, by the way.

 

I have some wheel bearing grease, actually. Is the cable on the Chicago Tools router able to be disassembled? I was thinking of using chainsaw bar oil, which could just be poured/dribbled in the end of the cable.

I'll oil the bushings on the pressure rods with the oil I use on my slot car oil-lite bushings. I forget what the X-axis rollers are in -- do they need oil, too?