Well, lots to report tonight. Some good, some not so.

One of the good things was that I figured out what I was doing wrong with TurboCAD. Long story short, I think there is a problem with the classic UI as it doesn't give the option to toggle between 2D selecting and 3D selecting. Or, if it does it is very well hidden and the experts haven't been able to find it. But, I switched to a different UI and there it was. One click and I was able to select the edges to chamfer. However, doing the chamfering is a compute & memory-intensive thing, so I only have 3 of the edges chamfered. Maybe tomorrow or Monday I'll get them all done.

However, in some ways it may be a moot point. That's 'cause the guy at Tulsa's FabLab says we won't like what we get 3D printing the plate. We loaded up the STL file and discovered several errors in it, although the "fixer" program they have there made short work of the errors - apparently they are pretty typical. Anyway, looking at it he said there are at least two problems. First, it would take forever to print since the printers will go around each hole many, many times to build the thing. And, I'm guessing that in doing so there will be many places where the last layer will be cold and the next layer won't bond well, but he didn't say that. However, the other problem is that he thinks it'll come out warped - even from Shapeways, and he's used them for a lot of his projects so knows them well. But, he said to discuss it with them as they may be able to figure something out.

As for how to make the plate, he suggested this:

1. Mill the plate using the CNC mill. Remove all of the excess material, leaving the plate with the lips, bosses, and walls, but without the 864 holes.
2. Change to a drill bit on the CNC mill and drill the 12 hold-down holes
3. Move it to the laser cutter and cut it to the octagonal shape and cut out the 864 holes in the top of the plate. (He took a 1/4" thick piece of plastic and cut 10 holes, each .300" in OD in a 5x5 grid, and then cut out a 2"x2" square that contained the holes. Took him maybe 5 minutes to put together the drawing and have the laser cutter do the work.)

However, that doesn't put the chamfer on the top edges, which would take a 5-axis mill instead of the 3-axis they have. One option would be to mill the outside lip thinner than 3/16" so the edge isn't as large. Maybe 1/8"?

I know that isn't what we wanted to hear, but he works at FabLab and has made 3D printers, much less used a bunch of them. So I'm guessing he knows a lot about them and if he says we won't like it then we'd better slow down and at least ask a lot of questions.

 

5-axis, is he nuts?
Just use a 45 degree mill and indicate each pair of diagonals on the octagon with travel of the table.
Obviously the four sides can be cut in one go round.

This is why I thought the acrylic would allow more detail (like the 'pleather' grain) and there are no issues with infill or bonding of the MMO.
Once catalyzed the Tg is over 220F.

Do they have a waterjet?

 

I think the reason he didn't have a way to cut the chamfer is because they only have two mills:

• Desktop: It has a working area of 6" x 8" so isn't large enough.
• Shobot: Takes up to a 4' x 8' sheet of plywood. And while its resolution is said to be .003" he thinks it is more like .015" - on a good day. It would be big enough, but he was concerned about the accuracy. Apparently it is mainly used for woodworking, and they were doing just that with it today.

Obviously if I were to do it here I could put it in my mill and chamfer it. Or, we could see how the Shobot does. But, the whole idea was to do additive manufacturing, and he doesn't think that is going to be a good solution for this.

 

Sorry, I forgot a couple of things. First, they don't allow use of acrylic, just ABS and PLA. Second, no waterjet.

 

Acrylic (PMMA) is not extruded, it's polymerized with a pair of UV lasers.

The Formlabs printers work this way.
But they only have a 5x5x6 3/4" build volume.

 

That is disappointing.

 

Yes, it is disappointing. But maybe Shapeways would say otherwise?

 

Been following as much as i can of this.

I think it would be a great piece for many people.

Could you make the plate and rather than make all the holes, make them dimples instead? Wouldn't that make a more solid part to decrease warpage? Couldn't people drill out the dimples if the chose to run a speaker in that location.

Basically make it a speaker delete with the option to be functional.

 

Kyle - You may be onto something. Making it without the holes would certainly speed it up, but drilling 864 holes would be a daunting task. Why not make this a two-step process - have the plate printed without holes and then cut the holes with the laser cutter. That's assuming it is the length of time needed to print all of the holes that causes the problem, and this would speed things up significantly.

I just looked at the list of things FabLab allows to be cut with the laser cutter. ABS is on the list, and a lot of the interior parts on the trucks are of ABS so maybe it'll live on top of the dash. Also on the list to cut is nylon, and the guy at FabLab said Shapeways can do nylon and it probably has the best chance of not warping.

Again, all of this needs to be discussed with Shapeways. What material would they recommend? Will it warp with/without holes? Do they have a laser cutter and could the holes be cut on it? Once the file is done, albeit probably with errors as I saw yesterday, then Ron can discuss it with Shapeways.

And speaking of errors, the guru on the TurboCAD forum has pointed out the error of my ways. Apparently drawing something in 2D, turning it into a 3D surface entity, and then turning it into a 3D solid creates lots of baggage in the file. It is much better to start by drawing a 3D solid.

So, that begs the question of what's the best way to make holes. I did the same thing with the first hole, meaning started in 2D, and then copied it 863 times. However, having downloaded the Platinum version of the program I find there is a tool to make holes. Might that make an even cleaner model? (I also found a "thread" tool, so I could easily put threads in the holes and use machine screws!)

Anyway, good idea!

 

Hmmm, Dimples may be the way to go. May deliver structural integrity, and actually, how many of us really have a dash mounted speaker now? most have probably modified to a 4 speaker system with a sub somewhere.

I don't think a plain "Hole delete" will fly....much too plain.

True "through-holes" is best, deep dimples may have to be second best.
How about doing the chamfer on a good old fashioned wood working router or shaper after the fact?

Yep, 863 holes is rather time consuming, (did it twice on a drill press).....

 

Well, I finally reached a stopping point with the file I created. The shop computer crashed, twice, while trying to handle the file, so I took the advice of the guru on the forum and started over. Or, more correctly, I took his file and took out a bunch of things he had done, like all the filleting as well as the holes. Actually, I just deleted the Boolean operation where the 7/64" diameter cylinders he created were subtracted from the plate, leaving holes. So, that left me with the plate, the walls below, and 864 red cylinders sticking through the plate.

Then I chamfered the plate and started placing the screw bosses in the walls as those were conceived after he drew the plate so need to be put back. And I hope to use the "threaded hole" function in the software to create the holes for the screws - anyone for #8 machine screws? And then I'll tackle the holes in the plate. However, I will save it before I put the holes in. That way we can have the plate made in one step and the holes done in another step if we want to.

 

I thought I was "there", but now see a few glitches and don't know what they are. So, I'll be taking this to the TurboCAD forum asking for more help.

But, the plate is chamfered on the top edges - although I forgot to round/smooth the other edges that you asked for, Ron. Sorry.

Anyway, I have also re-drawn the "walls" to add in the bosses for the screws. And I moved them to get them more evenly distributed around the periphery of the plate. Also, I used the "threaded hole" tool to do this, so hopefully the holes will be threaded 8-32 when the printing is done. And, they are supposed to be threaded .500" deep, meaning the threads extend into the top of the plate, not just the walls. Also, I put a 1/32" chamfer on the entrance to the screw holes - just 'cause I could.

So, here's a view of it.




Here's a shot from the bottom showing the bosses and the chamfered and threaded screw holes. Plus it shows a bit of the problem - the triangular area on the upper left where the holes don't come through.





Here's a close up of the bosses and screw holes.

 

Is there going to be a bottom plate under the dash pad to sandwich the top down to the pad?

 

The plan has been to use screws in the bosses, with washers, to pull it down against the top of the pad. However, I've wondered about making a matching plate that would sandwich the pad between the two parts. Thoughts?

 

I think a sandwich ring would be nicer looking. Especially if they could be produced and sold as a dash fix.