DIY - best materials for printer parts

[mlee]

So I'm in the middle of designing and building my own printer based loosely of the FT5-R2. I'm going to have three independent z motors and three lead screw to try and get true auto leveling.

I'm stuck on materials to make the print bed plate out of. I'm thinking of a one piece solution, see the image...

I was trying to source Aluminum Composite, kind of difficult to get, especially if you want the really good stuff like want ALCOA makes. I was thinking Carbon Fiber, but I am concerned about the temperature, even if the bed is 20mm away from it, it could warp over time. The Dragon Plate solid carbon fiber brand has a temp rating of only 60c, far too low.

Any thoughts on other materials? Anyone have any good sources for 6mm thick ACM?

Thanks

Mike

[csorrows]

I would use something like 6061 mill stock. 0.250" should be stiff enough. The only issue is it is difficult/expensive to find above 12" x 12". Maybe step away from one monolithic plate?

Materials are more difficult and expensive to find these days.

[Ron]

As odd as it may sound, 3/8" (8mm) cabinet grade plywood might work.
But you might want to add some stiffening ribs like I did to mine (1.25" leg aluminum angle, 1/32" thick).
Just be sure to coat the side that faces the heater plate with aluminum foil tape to act as reflective barrier insulation.
It is surprisingly effective at keeping things cool.
I did that on my FT-5 from the start and the melamine only gets slightly warm despite the hot aluminum plate above it.
I built a detached garage a few years ago and used reflective barrier insulation without any fiberglass batting and even on very hot days it remains cool inside.

Oh, and for what little it may be worth, I have a patent on a high temperature optical sensor that uses that principle to stay cool, so I know for sure that it works if done correctly.

.

[mlee]

I would use something like 6061 mill stock. 0.250"

I would go with Aluminum, but I only have a Shapeoko CNC, milling that would be a nightmare.

coat the side that faces the heater plate with aluminum foil tape to act as reflective barrier insulation

That is a great idea, maybe carbon fiber would work then...for the leveling aspect, I think plywood would add too much weight for as thick as it would need to be.

I did get a line on some ACM locally, I have to buy a full sheet though, 4'x8'. Could be worse.

[Ron]

The main things to remember about reflective barrier insulation are: an air gap is absolutely necessary; the surface needs to be shiny and as clean as possible; and at least some air flow is required.
Because the plate as shown in your image has the four center holes air flow should not be a problem.
You can use kitchen aluminum foil as the barrier with the smoother side up and just glue it to the platform.
Then the leveling springs should provide the gap, but I would suggest 3/8"-1/2" at least (mine is in that range).

We also have reflective barrier insulation in our attic and it is incredibly effective in the summer time, even better than fiberglass batting.
But its efficiency decreases as it becomes coated in dust over time.

As for plywood, cabinet grade plywood in 3/8" thickness does not weigh that much and it is very rigid.
And if you Swiss cheese it out as shown in your image it will become even lighter.
But if you can buy ACM, all the better.
Perhaps you can reduce your net cost by making up "R3" plates with the extra material for others as well?

[mlee]

Perhaps you can reduce your net cost by making up "R3" plates with the extra material for others as well?

I would be happy to. I'm "posing" as a sign maker and getting a full sheet of MaxMetal 6mm white. I think I'll have some leftovers...(I have made signs for $ on my Shapeoko, so technically I'm in business...)

Once csorrows has an STL of his R3, I can make several plates. I have a larger Shapeoko at work, about 18" x 44" machining area. I've found the speeds and feeds and have a few upcut 1 flute bits on order.

[Ron]

Very nice, sounds like a plan..!
That is one tool I do not have (CNC mill or laser cutter).
I have an Enco bench top mill, but it is completely manual.
I have been toying with the idea of converting it to CNC using MACH3 hardware, but at the moment I am just too busy to tackle such a thing.
I have a friend up the peninsula from here that did exactly that and swears it works great.
Maybe sometime later this year I'll give it a try.

MaxMetal's closest pickup location for me would be Hayward, CA.
Tempting indeed.

[csorrows]

Wait, are you suggesting the R3 should be an open project? I have thought about exactly that. We have a handful of very bright minds here on the forum and I think it would be good as a community project. My concept is no where close to a final design. It still has issues.

The one big glaring issue is that I design in Sketchup. Most people don't use it and don't have experience with it.

I could talk to John and see if he minds and it is technically based on his original design and work that I was commissioned for. However, all development time spent on the R3 concept was 100% my time.

Sorry to hijack your thread, I think I need to start a new thread focused on the R3.

[Ron]

Interesting.
If you could export the parts in .igs, .stl or .stp formats I could import them into the .ipt format which is used by Inventor and Fusion360.
I could also convert them to .tcw format for TurboCAD, which is fairly popular.
And TurboCAD can directly open .skp files as far as I know (at least my version can).
So there are a number of options available, I would think.

[csorrows]

I created a thread in a secret area of the forum for this discussion. You and the other trusted members have access to it.

Fight Club is a go!

[end of hijack]

[csorrows]

I actually love the idea of ACM for a 3D printer. In my mind, it's a very good material for the use. Keep us posted!

[mlee]

Given how pickup went, and that they were more than happy to sell to me, I can easily get US made ACM, MaxMetal Brand, 6mm thick. Either White or Black. As soon as my end mills arrive, I'll try some sample parts and see what is what.

[csorrows]

A word of warning about machining ACM. Because it is 2 different materials (aluminum and ABS) speeds and feeds will take a bit to get dialed in. That was the reason for the burrs on the ACM parts from Folgertech.

[mlee]

http://cncfaq.us/ufaqs/what-is-the-correct-end-mill-and-speeds-and-feeds-for-dibond-or-maxmetal/

Exactly my concern, this page has great info, and most importantly the part number for the right kind of end mill. Should arrive Saturday.

[Ron]

Just curious, I did not find pricing on their website (but perhaps I just didn't look in the right place).
How much was a 6mm thick 4'x8' sheet, if you don't mind my asking?

[mlee]

$109 and change with tax. I figure I have enough to make at least 3 complete printers perhaps more. The quality and rigidity is surprising. It is comparable to the rigidity of a sheet of 3/4" Hardwood plywood.

[Ron]

Wow, that is excellent.
While it may seem a lot, have you priced plywood lately?
Thanks!

[mlee]

First run, some test pieces I Resin Printed to check my measurements for fit. This pic is the parts done and untouched.

This is a close up with the protective film still on.

Film off. I am very pleased with the quality of the cut. Almost no finish work needed. You can see the tabs I have Fusion put in to hold the piece. I am not a fan of the double stick tape method, Clamps, clamps, and more clamps. These trim off with a utility knife, I'm sure my sander will make short work of them.

The fit is identical to the Resin prints...

Very nice results!

[csorrows]

That is an excellent result for a first try! Amazing outcome.

I don't think John was using anything to hold the sheet down besides clamps on the edges and I know he didn't use tabs. He did mention the workers being afraid of the CNCs because they would throw the random small part out. Less of an issue with a downward bit but will still throw something if caught just right. He wanted me to avoid recesses as much as possible because they would not always come out the same depth which tells me he certainly would not hold the sheets down except for the edge.

[mlee]

Everytime I tried any type of clamping that wasn't mechanical, eventual failure...as I was researching this, I watched a guy use his hand to hold the piece down.....

Fusion has a great tab feature when you do a contour pass. Those tabs were only 0.5mm thick, but they never moved during the machining.

On the main holes, I ran one as a pocket, and the other as a contour, KNOWING that a little bit would most likely fly out. I'm sure that what John's employees experienced. I did this to see if there was a difference in tolerance, since there wasn't I'll do them all as pockets to avoid the little bits. The main problem with that, is that those small bits can jam the endmill messing up your part.

Glad you like the result. I hope to have some parts made soon, I still working on the design.