nidal published a new build:

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So, I've got my ACME nut blocks (http://openbuildspartstore.com/8mm-lead-acme-nut-block/) and I've been trying to get them to move smoothly on ACME rods (http://openbuildspartstore.com/8mm-metric-lead-screw-acme/) for the past hour and a half (four pairs of nuts/rods).

I did what advices I found here on forum suggested:
- used a drill to work nuts out on their rods
- bought graphite lubricant and sprayed nuts with it
- then went on and sprayed rods the entire length (nuts are so tight they mostly clear lubricant off the rod)
- used drill some more

I managed to have one nut on one rod rotate smoothly (I can rotate rod with tips of my fingers, this is kind of resistance I've got on my current 3D printer when I rotate Z-axis rods) but others are still a pain in the butt to rotate.

Anything else I could do to work out those threads in nut blocks?

Also, what do you do to straighten ACME rods? These are 770 mm long and two of them have bends I can't really notice with a naked eye when looking down the rod. But when I rotate them in the drill they tend to wobble quite a bit.

Thanks!

 

This is what I did at the end to get ACME nut blocks moving:

- There were 4 pieces, each about 25 cm in length, of ACME rods left after I cut them to required length
- I chose one out of those 4 that required most force to turn nut block over it
- Then I basically made thread tap out of it by cutting 3 notches at the tip with dremel metal cutting wheel
- Threaded all nut blocks with this tap from both sides few times and it did remove very small amount of plastic out of them

Now ACME rods can be turned using just fingertips. There still are some issues but it is waaaaay better than when I started.

 

All axes connected to gantry plates. Those nut blocks were, well, nuts

 

Yes it's gMax, black and blue It's a good printer, I just haven't managed (yet) to get mine to print anything I could use in builds. even when I get parameters right, next or third print is off and I have to start calibrations and play with parameters all over again. Must be some mechanical issue.

Anyhow, bed should roll on two 20x20 v-slots or maybe even on top of Y-frame 20x40's.

I'm trying to make everything from off-the-shelf parts, so you could just order bunch of parts from openbuilds and/or some other store and put it all together without the need for 3D printed parts or custom made aluminium plates etc. However, it turns out that end price could be an issue with that kind of build.

As for how the parts would come out on this big of a printer, well, the idea is to be able to print a number of smaller parts in one go. Put the plate on, start print, print finishes, take the plate with parts off, put the other plate on, take parts off of the first plate, and round and round you go.

Also, you should be able to take the head off fairly easily and put some other on (i.e. DIY Dremel or not-so-diy spindle) and use it as a router for plywood, balsa and similar stuff.

We'll see what happens with this one, but the way things are now (I have tried different setups, screws, belts even ball bearing screw for Y-axis), it seems that I will have to make some custom aluminium plates and brackets and use parts that you don't find in online stores that often.

 

Thanks Val!

I was thinking about 12mm screws at some point but since I've already got 8mm ones I will give them a try first anyway. I've got wrong screws a month ago in my first shipment and tomorrow I should get the right ones. The ones on these images are with 2mm lead which is precise and requires lower torque to drive, but they are fairly slow. There's an 8mm ballscrew lying around somewhere and I'll probably drive Y axis with it just to try it out. Those things are expensive but sooooo smooth, studry and precise. Wow!

It turns out I could build almost entire setup like this by finding parts in online shops and without having to source parts from china. This is good if someone wants to build one without having to spend time on alibaba.com asking for quotes and stuff (well, maybe you could find some, or most, of the parts on aliexpress, didn't search there).

Downside of this build is that it is really not that easy to put it together and have everything under right angles and properly aligned, which becomes important when you work with 750mm extrusions. 3-4 degrees off the right angle and it is 3-4mm skew on the other side of the span. It is especially tricky to tighten and align wheels on Z axis carriages, the way they are assembled right now. Y axis is not that straightforward either, but it is a bit easier to put together. This needs re-engineering and I'm thinking of making custom plates which should be way easier to align and much faster to put everything together.

CNC bot I ordered should be shipped in by the end of the month and I will be able to make some custom aluminium plates with it. This kind of beats the purpose of having no custom (or 3D printed) parts in it, but hey, if it is too hard to assemble and you can't build anything with it, then it doesn't matter that you can get all the parts for it from 2 or 3 online shops by the end of the week, right?

 

Quick update:

I have modified a frame a bit, but it is done now, all parts have arrived and are assembled:




Extra v-slot beam is another version of X-axis drive using belt.

Here is how maxbox frame compares to gMax:


That window above maxbox frame fell of the other day due to strong winds and did some small damage on the frame:


Nothing terrible, few notches and misaligned bits. Landlord came just an hour ago and nailed that ******* back into it's frame, no more falling windows! I hope...

Next is electronics, got all the drivers, PSU, and will use one of the boards I have laying around to test drive it.

Speaking of boards and firmware, if anyone is interested in running Arduino sketches and libraries on controllers other than Atmel,
I made a portable (as in "can be ported to other platforms") version of Arduino source code: Arduino-XC. I have few cosmetic things to finish up
and I'll release it as FOSS in 3-4 weeks.

I even made Indiegogo campaign for it, you can take a look at it here: http://igg.me/at/arduino-xc

Relax! No need to pledge to any of the perks and give any money for it! By the time the campaign counts down to zero, I'll tie loose ends on Arduino-XC that need to be tied up and then I'll release the source on Github. You can have a look then and maybe even use it, if you're interested.

That's it for now, back to the grind!

 

Can't fit into photo, eh?
Nice!