Testing New Materials: Feb 22 Update

Hi everyone!

Hope your Wednesdays are going well. Before I dive into this update, I just wanted to fill everyone in on a small detail of the updates that we realized we have never clarified. Starting about 2 months ago, Hannah and I decided to switch off on the task of writing the update every week. This week is my (Bar’s) update, although Hannah will add in a little blurb at the end. It’s not a big deal, but we thought some might be curious or this might clarify some things about the weekly updates. If you’re curious to figure out who wrote which update, you can generally assume that whoever signed off first at the bottom of the update, that’s the person who wrote the update for that week :)

Now onto the good stuff! The week before last we asked what you wanted to see more of, and the response was overwhelmingly that you wanted us to test more materials. Because of that response, this week I went to the hardware store and bought as many of the materials you asked for as I could find. This week we are going to be testing:

Construction materials:

If we’re serious about making a machine that can let you download a house, it has to work with the materials used to make a house.

  • Oriented Strand Board (OSB) - A cheap alternative to plywood made from bonding wood "strands" instead of the "plys" that are used to make plywood. Often used in bulk for construction because of low cost. 4’x8’ Sheet Cost: USD $12.15 (http://www.homedepot.com/p/7-16-in-x-48-in-x-8ft-Oriented-Strand-Board-386081/202106230)
  • Rigid Foam Insulation: -A rigid foam insulation used to insulate house walls. Also a lightweight material useful for other projects. 4’x8’ Sheet Cost: USD $12.95 (http://www.homedepot.com/p/R-Matte-Rmax-Plus-3-1-2-in-x-4-ft-x-8-ft-R-3-2-Polyisocyanurate-Rigid-Foam-Insulation-Board-754404/100572981)
  • Drywall (Sheetrock): A panel made from compressed gypsum dust used to cover the interior walls of houses and add fire resistance. 4’x8’ Sheet Cost: USD $10.98 (http://www.homedepot.com/p/Sheetrock-UltraLight-1-2-in-x-4-ft-x-8-ft-Gypsum-Board-14113411708/202530243)

Plastics:

  • Corrugated Plastic Sheet: A light weight plastic panel material similar to cardboard made from some type of plastic (feels like HDPE?). Provides great strength and water resistance at a very low weight. There are some companies which make very cool lightweight kayaks out of this. 4’x8’ Sheet Cost: USD $21.46 (http://www.homedepot.com/p/Coroplast-48-in-x-96-in-x-0-157-in-White-Corrugated-Plastic-Sheet-CP4896S/205351385)
  • Acrylic: Clear plastic, readily available commonly used because it laser cuts beautifully. 4’x8’ Sheet Cost: USD $~95.84 (http://www.homedepot.com/p/OPTIX-093-in-x-36-in-x-48-in-Clear-Acrylic-Sheet-1AU0593A/100250108)
  • Polycarbonate (Lexan): Another type of clear plastic, very tough, (250 times stronger than glass), somewhat less common in DIY projects because it cannot be laser cut safely. 4’x8’ Sheet Cost: USD $~162.62 (http://www.homedepot.com/p/LEXAN-36-in-x-48-in-x-0-093-in-Polycarbonate-Sheets-6-Pack-GE-38-06/202038091)

Other:

  • Medium Density Fiberboard (MDF): An “engineered wood product” made from wood fiber bonded together. MDF has no knots, grain or other natural irregularities. Does not handle moisture well. 4’x8’ Sheet Cost: USD $29.98 (http://www.homedepot.com/p/MDF-Panel-Common-3-4-in-x-4-ft-x-8-ft-Actual-0-750-in-x-48-in-x-96-in-M11161249097000000A/202332600)

For each of the tests I decided to cut out one of the motor mounting plates. It’s an interesting shape with small circles which make errors apparent, as well as curves, and straight lines which make it a good test candidate.

Motor mounting plate in Ground Control

Motor mounting plate in Ground Control

All of the tests were done with either a ¼ inch two flute spiral up cut bit, or a ½ inch 45 degree engraving bit. In each test the part is shown in the photo exactly as it came out of the machine with no attempt to clean up burs or sand edges.

The two bits used in these tests

The two bits used in these tests

Results:

OSB: Cuts decently well, more splintering than with plywood because the strands seem to be less well bonded together. I wouldn’t build a dresser out of it, but as a structural material, the cuts look good. It smelled a little funny while cutting, so I would recommend good ventilation if you are going to be working with OSB.

OSB motor mount

OSB motor mount

Rigid Insulation Foam: There are two types of rigid insulation foam, one is made from small foam balls similar to packaging foam and has a silver reflective foil on it, the other kind is made from a single sheet of foam with no noticeable balls and is generally a bright color (pink, blue, etc). I chose to test the kind with the small balls because I know from previous experience that the colored kind works well but makes awful dust. I was a little worried that the balls would split rather than cut, but cut quality was generally pretty good. The foil tended to pull away from the cut a little bit but that was the only issue.

Insulation Foam

Insulation Foam

Drywall: Drywall cut much better than I expected it to, and the dust extraction system made for a remarkably clean experience. The paper backing on the sheet rock pulled away from the cut similar to with the insulation foam, but a quick slice with a razor knife can take care of that.

Drywall

Drywall

Watching this (https://www.youtube.com/watch?v=eump3ODx9iU) youtube video inspired me to try to see if I could get drywall to bend the same way they did. I didn’t have quite the right router bit, but after a little touch up with an exacto knife I’m pretty pleased with the results especially on the very first try.

Unfolded drywall

Unfolded drywall

Because my engraving bit wasn’t quite tall enough the drywall couldn’t fold completely

Because my engraving bit wasn’t quite tall enough the drywall couldn’t fold completely

After a little trimming with an exacto knife it closed

After a little trimming with an exacto knife it closed

Coroplast: Coroplast cut quite well but seemed to result in less accurate cuts than I expected. Cutting the ¼ inch material in a single pass was not an issue, but notice how the mounting holes are not perfectly round. Less obvious in the picture is the fact that the straight edges also are less straight than in the other materials we have tested. It seems like the sled is sticking to the surface, possibly due to static electricity. The interior corrugated structure may also be a factor. More investigation is needed.

Coroplast

Coroplast

I decided to try the same “score and fold” technique that worked with the drywall with the coroplast and it worked well. The groves were less clean looking than in drywall, but I think it would be possible to build some very cool structures this way.

Folded coroplast

Folded coroplast

Polycarbonate: Polycarbonate cut well other than a little bit of a blunder on my part.  When I ran the test I hooked up one of the chains to the sled with a 360 twist which didn't agree with the sprocket so I had to redo this test. You can see the scar from where things went wrong on the finished part. I cut the polycarbonate in 3 .05 inch passes because I read online that people sometimes have issues with the plastic melting. I didn’t see any melting. I also tried something new which was to attach the material to the machine with double sided tape. It worked much better than I would have expected with the one exception: cutting through the material and into the tape gummed up my end mill quite a bit.

Polycarbonate (Lexan)

Polycarbonate (Lexan)

Acrylic: I bought only enough of both the acrylic and the polycarbonate to do only one test each and I messed this one up a little too. On this test I set the bit depth too shallow and only cut part way through in the interior holes. Other than that user error, acrylic cut well.

Acrylic

Acrylic

MDF: MDF is known for cutting beautifully and it does. You can see the mark left by each pass on the side of the part. A quick brush with sand paper would clean these off.

MDF

MDF

Because of how much we're trying to get done this week I didn’t have much time to dedicate to each material so what you are looking at is a pretty un-optimized first try with each. A small amount of effort spent finding the right settings for each material would probably pay off. Thank you for the material suggestions everyone! I’m sure I missed a couple, so if there are more things you would like to see, let me know in the forums!

Hannah’s addition: Hey everybody. So as I’m sure many of you can imagine, Bar and I learn so much every day that we work together on this project. Last week we had a bit of a disagreement about the update, but it resulted in a really positive conversation. This conversation, as well as some feedback from our backers, led us to realize that we want to be certain we aren’t leaving those who aren’t already CNC/engineering/tech-savvy in the dust. Hence the “No Judgement” channel.

Essentially the No Judgement channel is a channel in the forums where there are no dumb questions. If I had a dollar for every question I asked Bar that I thought was dumb, we could’ve made Maslow without Kickstarter (not really but you get my point). We want everyone in our community to feel welcome and “in the loop”, so the No Judgement channel will be a place where I discuss my mistakes and what I learn, as well as for others to post about similar topics and/or ask questions that might seem “dumb” to the more savvy individual. Additionally, I’ll try to use what is learned in the No Judgement channel to make posts/videos so the knowledge gained from the channel can hopefully reach a wider audience.

This channel is very much going to be an experiment, but we hope it turns into a place where anyone feels welcome to post. If you’d like, go ahead and check out out here. I’ve already started one thread about some of my woes with SketchUp.

ATTENTION BETA TESTERS: We have officially sent you the Backer Survey! Please be sure to respond to this ASAP, as we’re hoping to ship those kits next week!

Thanks for reading, everyone! As always, have a great rest of your week and we’ll be back next Wednesday.

The Maslow Team

Bar & Hannah