Some other notes about my heat bed experience.

I started out by using the Makerfarm 12x12 heated bed and got 12x12 aluminum to match it. This has honestly worked pretty ok, biggest thing was getting the holes in the right place which I did with a 1/8" drill bit by hand. In retrospect that is what convinced me I needed the drill press for my Dremel. The second biggest thing was that you HAVE to glue them together, any amount of air between the plate and the bed will mess things up. I used 12x12" double sided 3M tape that I snagged off Amazon and that worked great.

The only reason I made the new bed is because I wanted to use a mains heater rather than 12v.

If you decide to go the silicon heater route I recommend ordering your plate about 1/4 to 1/2 of an inch larger than your heater. In my case I ordered a 300mm heater and 312mm (12.25") plate. I would have liked to have a little more spare room probably (would make it easier to great counter sinks for screw heads and what not) so I would probably order a 12.5" plate if I were to do it again.

I have gotten two sheets of Printbite. One 300x300 and one 350x350. I used the 300x300 for the first bed and it worked great, it was slightly smaller than the 12x12 bed but was easy to install. I just finished using the 350x350 sheet and trimming it to size......that was an adventure. This stuff is HARD I went through about 10 x-acto blades and two box-cutter blades getting it cut to size.

 

I got mine from this seller on eBay for $41 shipped. I was worried about it being bent but it was packed well for shipment and seems to be wicked flat. The edges are a bit messy where they were cut, but that doesn't make a difference because I (usually) don't print off the edge of the build plate.

Yeah that's right. I imported the mounts into Fusion 360 which is how I came to figure out that it was angled (because when I measured the piece it actually says "Angle: 1*"). Fusion is much easier to work with because it does have some facility for lining up edges and starting your sketch on the vertex. I redid the motor mounts with 2mm extra clearance around them and finished installing them last night. I made a sound recording with one mount swapped and the print head moving in an X across the build platform. You'll hear just one motor, then both, then the replaced motor mount, then both again, and repeats. I think the image of it speaks for itself though.



Although I might have had something else messed up as well, because as I was taking the last screw out of the last mount, I said oh wait let me get a recording of something else as well. When I put as many screws back in as I had T-nuts still in place, the motor was *significantly* quieter and I had to touch the motor (to keep it in contact with the frame) to make it noisy again.

My mounts aren't as pretty as yours, it is just 3mm thickness on the bottom then 5mm thick on the top of the motor. The screwholes and shaft hole for the stepper are also pulled back 2mm and the piece extended out by the same amount. 2mm is overkill and could easily be 1mm or maybe even 0.5mm.

 

I think I only have the bare circuit boards (no parts) so you'll have to source the parts, assemble, and have an ISP programmer to make it all work. If you're still interested, PM me your address and I'll drop one in the mail (shipping is just the cost of a stamp, the board is like the size of a nickel).

 

Well ..... just working on the morning coffee, staring at my tap & die set in the shop. Aluminum extrusion arrived yesterday from Fuzztech. Wife is out shopping at the jewelry store so I think I'm in the clear to get started ... lol

Wish me luck!

 

Having an issue with Z axis movement, hoping others may have seen it.

I have a 8825 driver set to 32 micro stepping driving two steppers in the front and back configuration on my z axis. When I drive the Z axis faster than 1000mm/s the whole structure vibrates and the steppers reverse or skip most steps. I suspect I am just driving it too fast and the nema 17 steppers are simply not able to deliver the torque needed. Or my acceleration needs some tuning or the steppers, lead screws and delrin blocks are not aligned as possible. So more research is being done and I may just limit it to 1000mm/s a second on Z which is more than fast enough honestly. This is more an exercise in my trouble shooting and curiosity than anything else.

 

I am looking for stepper motors but I am unable to find something that satisfies the 68oz-in requirements.
I have found however these:

17HS19-1684S1
Motor Type Bipolar Stepper
Step Angle 1.8°
Holding Torque 45Ncm(64oz.in)
Rated Current/phase 1.68A
Phase Resistance 1.65ohms
Recommended Voltage 12-24V
Inductance 2.8mH±20%(1KHz)

Running these at 12V from a ramps or rambo, would I have any issues?

 

Sorry, I can't speak to those steppers with any expertise. But I can say the below if you are interested.

I'm running Kysans with a stated 76.4 holding torque, so far they are great and plenty strong. BUT, I've not printed with them yet. I've moved the XY bar as fast as I dare go, change direction quickly, tested various movements during driver voltage settings and they've been rock solid. They are not cheap, but I have 0 buyers remorse so far.

The one caveat, I am currently troubleshooting any issue with my Z axis steppers reversing during very fast moves, but I suspect it's me pushing the mechanics too fast and not optimizing the settings yet. The motors themselves do not appear to be the issue.

http://www.amazon.com/Kysan-1124090-NEMA17-Stepper-Motor/dp/B00IEVE4MC

 

Unfortunately I am in the UK and the postage is prohibitively expensive.
I am looking for something in this country, or may be taking the risk of buying from China direct.

 

I hear yeah, did a little digging found the items below. First one is a couple years old, but who knows... Good luck!

Google Groups
Kysan 1124090 NEMA17 Stepper Motor from Kysan Electronics | US toy

 

I'd be interested in the eagle file as well as the STL and BOM.

I'm always up for playing with something new.

 

Hi Capnbry bro,

i have a similar build on the belt driven z lead screw with F608ZZ and 36T 2GT pulley. Would you mind to share more photo of it and how do u secure the lead screw from the bottom? Is it plainly but the screws in the pulleys?

Thanks in advance

 

Well, I learned yet again some valuable lessons this weekend.

1) Double check the amount of fasteners required
2) calculate belt length required AFTER deciding to alter/scale design

Yep, I ran out of t-nuts and I was about 2 inches short on my GT2 belt .... this caused the excess use of a few 4-letter words... lol

All in all, it's gone well so far. Tapping extrusion by hand however gets to be a pain and is quite time consuming.

26099579370_e99cc0c7ca_k by wackocrash5150 posted Apr 11, 2016 at 12:56 PM

 

No sir. It was my own blunder. I mis-typed on the order sheet for the t-nuts. As for the belts, I ordered them about a year ago when doing initial planning from your original dimensions. Since then I decided to upscale to a full 12x12 build (even though my plate at the moment will be only 12x8) seeing that it was only a couple bucks more in aluminum. I forgot to take the belt into consideration as I'd only ordered 4 meters. Turns out that 2 meters on each belt is about 2 inches too short. So close, yet so far away! lol

Your BOM was good. It was just a brain fart on my part ... lol

 

What are you using to tap them? That was one of the parts I was most worried about, but aside from the tap I broke it turned out to be pretty smooth..

 

I got really lucky (to a point). I had changed my mind after ordering and went with a 12x12 bed. Luckily the person who I ordered the belts from cut them long and I ended up with about an inch to spare. Although I had already re-ordered the belt so now I have backups.

 

I know it's not professional and probably frowned upon, but I used some WD-40 and a Harbor Freight Drill/Tap/Deburr bit. I can't say I was all that gentle either. Turned out just fine.

 

I picked up a Tap & Die set from Canadian Tire a few months ago that's not bad. It was also recommended that I use some compressor oil for lube. It didn't work out too bad but this (Tap Jig / Holder for Aluminum Extrusion 20mm / any width Misumi, OpenBuilds v-slot, MakerSlide compatible by ProtoBuilds) also helped quite a bit to get the threats started.

 

I'd never tapped threads before this but knew I would have to. The first couple turns are easy, then its 1 turn in, half turn out, repeat, repeat, repeat, repeat, repeat, repeat ..... and I also had to clean the flutes frequently. I'd heard horror stories about breaking the taps off inside so perhaps I was being over cautious.

 

The jig seems like a good idea.. I had no idea what I was doing, but luckily the tap that broke did so at an angle, so I was able to pull it out. After that I just kept backing it out every few mm and cleaning the tap. No idea if I did it the "right" way, but it seems to have worked.

 

Nope. You were not being overly cautious! I had an old tap set from Harbor freight. It was super cheap and I was overly aggressive. Broke it off in one of the holes. Ended up going to the hardware store and getting a single, much higher quality tap. Pre-drilled the holes out and then tapped them all out squirting lube on the threads about every half turn and backing it out a bit every couple of turns to remove the shavings. Once I got the technique down it went quick. Had a rocky start, though. Ended up just filling down the broken off end of the tap and leaving it in the extrusion. Nobody will ever know... wait..

 

Same. Exact. Thing.

 

Ok then, so despite my forgetfulness, looks like I did something correctly. Lol

I'm very excited about this build. I've converted my RAMPS to run off a 24v PSU that I have on order. Anyone else done the same? I considered another SmoothieBoard of some sort but read on here that it was a bit overkill, so I modded the RAMPS

 

I looked what it would take to modify my RAMPS and didn't think it would be worth it. But when I went with the A/C powered heater, I didn't need the 24V so went back to 12V.

 

Mine wasn't that hard. All I did was remove the poly-fuses and put some inline automotive fuses in and remove the D2 diode. I already had the fuse holders sitting in a drawer and the caps on the RAMPS board were already 36v rated.

 

hey guys ive got a problem i could use your smart help with

my print bed is going to be 17"x17" with a bed that big, the weight becomes a serious issue.

im trying to figure out how heavy my bed gantry can be to determine how thick the build plate can/should be. so i could really use some double checking and cross reference by you guys, the people smarter than i am.

i have 2 lead screws, and 2 motors. each motor has 84oz-in of torque. which is about .593newton/meters

the lead screw is 8mm diameter, so we will say that at most the torque on the screw from the weight of the bed is applied at 4mm from center right?

force = torque/distance

F = .593n.m / 4mm

F = 148.25 Newtons

148.59n = 15.11kgf

CONCLUSION: my motor will lose hold of a position with approximately 15kg of weight on the lead screw

so by this math, i can safely see that my z bed gantry and anything i print can weigh up to about 10kg without worrying about my motors or lead screws losing place in the z direction...right? does that seem at all correct?

Am i possibly missing parameters, like how long the lead screws are or how far up the print bed is? would anything else affect how much weight the motors can bare?

 

You might want to consider going with a 3 screw setup. Also, using a 2 start lead screw instead of a 4 would help keep the bed from falling when power is turned off.