Building the Quantum ORD Bot

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Building the Quantum ORD Bot

Postby dalewheat » Fri Mar 30, 2012 3:21 am

I got my Quantum this morning! I'm sitting at the kitchen table, right now, putting it together.

I know Bart would probably like some sleep just about now, so I'll address my questions to the community at large. I haven't been reading every post to the forum, but I know a lot of information is scattered across many posts. I'd like to cover the easy stuff here, and ask the simple questions that are going to come up a lot as folks start working on their ORD Bots.

I've got most of the gantry built, and I'm stringing up the timing belt. I'm thinking the posted instructions on the wiki refer to a fixed timing belt loop. I saw the last-minute design of the belt-clamp, but I've still got a couple of questions before I start snipping timing belt.

The "Folded Belt Clamp" B17058 attaches to the extruder plate with 2 M3 x 10 button head cap screws (BHCSM310S), yes?

Do I just pull enough belt across the pulleys and a little more to fold back over each end, then snip? Or is there an exact measurement available? The belt was not listed on the gantry drawing D30051.

Edit: Does the folded belt clamp capture the belt (cutouts facing plate) or expose them to the outside? Eyeballing the belt path, it looks like it should capture the belt.

I write technical documentation for a living, as well as ship out kits, so I know there's a lot more work to do before this is an "easy" project. I'm happy to ask "silly" questions as well as answer them. Let's work together to get the wiki up to speed so that more folks can enjoy Bart's handiwork.

Dale Wheat
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Re: Building the Quantum ORD Bot

Postby bdring » Fri Mar 30, 2012 3:50 am

I got the feeling that people were more interested in me getting these shipped than waiting for perfect documentation. Everyone is welcome to help with the Wiki.

I think there is a close length number on the wiki for the Quantum but not the Hadron.

If you wrap around the pulleys and cross over the clamp and hang each end of the belt over the ends by about 3-4mm, that is about the right length. Be sure that the idler is slid in a little so you have room to move it back to tension the belt.

Here is a rough video on how to install it. This batch of belt installs a lot looser than the last batch so I like to add a drop of super glue were the belts mesh. The belt should only be tensioned to about 6-8lbs.

Bart
"If you didn't build it, you will never own it."
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Re: Building the Quantum ORD Bot

Postby dalewheat » Fri Mar 30, 2012 3:57 am

Bart,

You're right. I would rather have this thing here, playin with it, building it, and asking questions, than waiting.

Why are you still up? Isn't this a school night?

Thanks for the video! I'm sure all the pieces of the puzzle will eventually fall into place. I'm just more cautious with parts that I can't un-cut.

I'd be happy with adding a note or two to the wiki as I come across things. Do I need special credentials for this?


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Re: Building the Quantum ORD Bot

Postby bdring » Fri Mar 30, 2012 4:06 am

Thanks for the offer.

I think the Wiki is open. I can always roll back changes I don't like.

In the future, either start a build log to show your build or start a topic like you have done, but give the topic a more search friendly title, so others in the future can find help easily. Some of these topics are going on 20-30 pages (mostly mine :oops: ) and are not the best for newbies to use at a later date.
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Re: Building the Quantum ORD Bot

Postby dalewheat » Fri Mar 30, 2012 6:17 am

The mechanical build is complete. It took roughly six hours, and that included a couple of false starts, testing for perfect fit and quite a bit of "apple polishing".

Tomorrow I will perform an electrical test and see if I can move all the axes under computer control. Wish me luck!

Here is a picture of the completed unit. I decided not to dress the wires through the infrastructure. I have another plan for sleeving the cables.

The build went very smoothly. I ended up with only a single T5 nut left over and two of the T4 nuts with set-screws. No parts were missing.

The device moves smoothly in all directions. The MakerSlide system is quite impressive. It would be even easier to adjust if I had the right 8mm open-end wrench to adjust the play in the V-groove idlers.

Good job, Bart!
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ORD Bot Quantum 044.JPG
ORD Bot Quantum built by Dale Wheat on 29 March 2012
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Z Lead Screw Nuts

Postby bdring » Fri Mar 30, 2012 1:15 pm

The first thing I would do is disconnect the Z lead screw nuts from the carriages. Put something about the right height on the build platform to support the Z temporarily. Use the motors to run the Z nuts up and down many times. This will break them in. I used some silicone spray lubricant too.

When you are ready to reinstall them, connect them back to the carriage very lightly. Make sure the Z is level by manually twisting one motor. Now run the Z up and down and the nuts should self align.

Most people know how to do this, but...slowly tighten the screws. If you fully tighten one screw at a time the nuts might try to rotate, so alternate screws as you are tightening so they do not rotate.

I was able to get pretty high speed out of the Z, but you really don't want too much or the screws will start to whip. I expect to see a few printed bearing blocks for the top of the screws coming from the community.
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Re: Building the Quantum ORD Bot

Postby crispyfry » Fri Mar 30, 2012 2:04 pm

I expect to see a few printed bearing blocks for the top of the screws coming from the community.

If you tightly constrain both ends of the Z rods you're going to end up with the same problem the Prusa design has when people add the bottom Z idlers - if both ends are fixed the rod is effectively overconstrained since the moving stage is fixed in the horizontal directions. In Prusa, since the rods have the same dia as the frame this means the frame bends. With Makerslide this may not happen, since it is so much stiffer than the lift rods. You want to design it so that any wobble or misalignment is allowed to self-dissipate in a way that does not affect the print head.

If by whipping you mean that the dynamic forces cause the rods to come out of alignment, then loosely constraining the top of the rods could help without getting into the problem of overconstraining the rods.
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Re: Building the Quantum ORD Bot

Postby bdring » Fri Mar 30, 2012 2:18 pm

When the Z is low and there is a lot of exposed rod it can whip at very high speeds. I lowered the speed to where it stopped and am still quite happy with the Z speed.
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Re: Building the Quantum ORD Bot

Postby JeremyBP » Fri Mar 30, 2012 9:11 pm

Dale, congratulations! It looks like your build went nicely. Please do make changes to the wiki where things could be clearer.

A while ago I was discussing putting bearings on the lead screws with Bart. I finally got around to trying it, and found exactly the problem crispyfry mentioned. If the z rods aren't perfectly staright (which screws rarely are) it binds. I ended up going back to leaving the tops loose.
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Re: Building the Quantum ORD Bot

Postby dalewheat » Fri Mar 30, 2012 11:11 pm

Thanks, Jeremy. It went surprisingly smoothly, considering I really don't know what I'm doing.

When my Hadron arrives, I'll go ever it a little more slowly and make some detailed notes. There's a few things that I found to be quite baffling in the existing instructions, but I'm sure they can easily be corrected. Also, I can add some more detailed notes about what fastening hardware to use, and where, as well as how to orient certain pieces. These are not obvious, and I had to go back and forth between the instructions and the assembly drawings several times at a couple of points.

I've been able to run the motors back and forth using a 3 channel TB6560 driver and the funny little pendant that comes with it. I'd post a video, but people have seen a Quantum doing more impressive things than exercising the axes.

I'm not happy with the fit of the folded belt clamps. It doesn't take much to pop the belt out a tooth or two. For example, running into the ends, since I have no limit switches installed yet. I think it only needs a small shim to make a tight fit that really would hold up to a great deal of weight. Alternately, if you leave 10mm or so of the belt sticking out of the clamp, and have some way of attaching it to the rest of the belt, either with super-glue or some sort of tiny clip, it seems to hold quite nicely. The problem with it now is that I mount the belt clamp with the pocket facing the carriage plate, to better hold in the belt. If it pops a tooth or two, I have to completely remove the two little screws that hold it in to be able to properly re-seat the belt. I don't like re-installing screws in plastic threads too many times.

So how do you recommend I mount some limit switches? I have lots of nice mechanical switches I can use for this. Is this what the T4 nuts and set screws are for? Only one was indicated in the existing instructions.

I'm also concerned about the wobble in the Z-axis lead screws. I can't seem to adjust it out completely. I loosened up the nuts, without completely removing them, and ran the Z-axis up and down many times to "break in" the Delrin nuts. I applied a small dose of DuPont Teflon Silicone spray lubricant and made sure some got on most if not all of the threads.

The Z-axis seems to creep up and down non-linearly. It speeds up and slows down once per lead-screw revolution. I've tried re-seating the lead screws in the shaft couplers both at the top and the bottom of the axis travel. The only thing I haven't double-checked or adjusted is the width separating the lead screws across the X-axis, but adjusting the positions of the Z-axis motor mounts along the rail where they are attached.

If it sounds like a lot of complaining and whining on my part, it's not. I'm just trying to document some of the little things that I either don't understand or don't work the way I think they should (which doesn't mean much, truly). Overall I'm still quite impressed with the kit as such. Hopefully this will help others get their units assembled with less time and trouble.

If I can get it to work with Mach3, then I will post a video on YouTube. Wish me luck!


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