BackEMF's SmartRap 0.4.7 build

5 turns and the issue still exists.

Quote
BackEMF
5 turns and the issue still exists.

Why not try swapping the X and Y motor leads over and see if the problem still happens on the same axis or not.
That way the print will be turned around, should still print OK and will show if the problem is with the hardware or the firmware.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

Thx, great idea!
will do that tomorrow evening.

Didn't have much time but I managed to track down the problem. Swapping the X and Y made it clear that the issue was in the mechanics.. bearings turned into rocks... and in their turn did more damage to the rods then I expected. The bearings dug deep grooves into the rods, and that as an end result caused lost steps at certain spots.

So now I need to hack the y-axis, and again I notice how hard it is to build a 3D printer if you don't have axis to a 3D printer. But hey, that's part of the challenge :-)
And this gives me a new insight into the value of having a few '100% hardware store designs'.

I hope I have a bit more time next week to have a better look at this and to figure out a fix. Minor setback but educative, I will now start a search for the most simple and straight forward way to re-build the Y-axis.

I have given thought about printing the bearings from PLA. I will have to put this on my to-do list, as I have already greased mine but they seem sticky at times.

Quote
BackEMF
Didn't have much time but I managed to track down the problem. Swapping the X and Y made it clear that the issue was in the mechanics.. bearings turned into rocks... and in their turn did more damage to the rods then I expected. The bearings dug deep grooves into the rods, and that as an end result caused lost steps at certain spots.

So now I need to hack the y-axis, and again I notice how hard it is to build a 3D printer if you don't have axis to a 3D printer. But hey, that's part of the challenge :-)
And this gives me a new insight into the value of having a few '100% hardware store designs'.

I hope I have a bit more time next week to have a better look at this and to figure out a fix. Minor setback but educative, I will now start a search for the most simple and straight forward way to re-build the Y-axis.

Good idea to check the bearings from time to time I guess. I must look at mine and make sure they are OK too.

One way around this problem is to have a second printer that you can use. It also allows you to do multiple prints at the same time and get a job done quicker.

Maybe you could try something a bit different? I am going to try this as soon as I get a bit more time (must stop finding more things to do all the time) I want to try making some bearings using Delrin (also called acetal or Polyoxymethylene)
I have used it before for making Z nuts and it is the very best material I have ever machined. They never seem to wear out either and have a sort of built-in lubrication, but the material is hard unlike PTFE which is softer. It can be bought in rods and tubes, flat and sheets. I would say that you would still be able to use your damaged rods and they would still function well.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

I did check the bearings, i knew they are a weak spot and i already was printing replacement bearings, but now with the grooves in the rods they will damage the printed bearings so that's not really a way forward. I'm giving it some tought to do the Y axis a bit different. A few things i have in mind :

• Dry bearings, no messy sticky parts
• Flat slides instead of rods
• Keeping the moving parts as light as possible

Dry bearings, no messy sticky parts
Flat slides instead of rods
Keeping the moving parts as light as possible

And yes Delrin/HDPE/POM (eventually LDPE) came to mind but the local hardware stores don't have it... I will look at a more specialised shop.
Also looking online. The thing is that don't have a lathe or other fancy machines and I really would like to find an option thats low tech and 'local sourced' if possible.

I'm thinking HDPE square staff material on 20x20 square alu tube. Though i don't yet know if that's a good idea, will the alu-tube wear from or the HDPE?
I gave PLA a try on alu and then the PLA damages the alu-tubing.
Glass on hardwood is also on my mind, or glass on HDPE

Very true that it is good to have two printers, but this is the first, and I was printing parts for the second though I was not quiet ready yet.
And for a second printer I'm looking for a fixed bed or a z-bed style build. Too many plans and not enough time. :-)

On the ATX PCB I made a little progress. Sourcing the ATX connector in europe is a bit more expensive then i want it to be, and the cheaper shops are all on summer break...

Weird how during a recession it is hard to actually buy stuff.

Rebuilding the Y axis along the lines i suggested some time ago. So lets see what issues i run in to:



I've tested a few things and it seems to work, so tomorrow i'll scavenge a timing belt from a printer or scanner and try to drive it.

A recent image of my Smartrap. The wooden Y slides work better then expected. The bed no longer flexes as expected but it actually runs more silent and smooth then before.

MDF baseplate and Oak 'slides', a GT2 belt and pulley that I ripped out of a copy machine, and a cheap bearing with the same diameter as the GT2 pulley on the stepper.

Now the Z axis needs a more chunky way to mount. The improvement of the Y turned out to have weakened the Z. so now that one flexes.

I'm having some fun in the learning curve roller coaster.

Here is a little thing i put together in FreeCAD, a Genie hotent mount for the 0.4.7 style X axis.



It's straight forward so not the most elegant but it does what it is made for.

Hotend can be slided in the slot and eventually be secured with a zip-tie trough the square holes.
An M3 screw can be used as set screw to fine tune the auto level z-switch trigger. (this turns out to be more practical then via the controller menu's search, think, set procedure.)
At the back are 2 holes to mount a 30x30mm or 40x40mm fan.

Edited 1 time(s). Last edit at 07/26/2014 07:39PM by BackEMF.

Quote
BackEMF
I'm having some fun in the learning curve roller coaster.

Here is a little thing i put together in FreeCAD, a Genie hotent mount for the 0.4.7 style X axis.

[attachment 37295 GenieHotendmount.png]

It's straight forward so not the most elegant but it does what it is made for.

Hotend can be slided in the slot and eventually be secured with a zip-tie trough the square holes.
An M3 screw can be used as set screw to fine tune the auto level z-switch trigger. (this turns out to be more practical then via the controller menu's search, think, set procedure.)
At the back are 2 holes to mount a 30x30mm or 40x40mm fan.

Good idea about using zip ties, I never thought about that for a hotend. I must give it a try too.

As for the wooden rails, have you tried rubbing some candle wax on the wooden slide surfaces, I think that will help a lot as well.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

Here is a universal mount for the Genie. It has a 30mm fan cowl as well.
Maybe you can modify the simple plate that was designed to trim and drill to suit whatever base it was to be mounted to.
Takes the Genie standard mount that uses a pneumatic fitting for a Bowden setup.



Universal Genie mount

Edited 1 time(s). Last edit at 07/27/2014 07:15AM by regpye.

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci

The zip-tie isn't really needed yet, the printed slot came out so snug that everything fits like a glove, tough if there is a little play then the zip will just pull it square to the beam.

I will try candle wax as well though it is already soooo smooth, it surprised me, expected a bit like a drawer, but it turned out much smoother then that. :-) I'm trying candle wax on a peice of oak and sliding it across MDF and yes it slides even better.

makes me wonder... is there already a candle wax extruder? would be nice if we could print candlewax figures, some kind of extruder tube that can be loaded with wax pellets. pull the rope out of a candle grind or shave it into little pellets load a tube and print... Feed the pellets with a drill bit turning in reverse.

Quote
BackEMF
The zip-tie isn't really needed yet, the printed slot came out so snug that everything fits like a glove, tough if there is a little play then the zip will just pull it square to the beam.

I will try candle wax as well though it is already soooo smooth, it surprised me, expected a bit like a drawer, but it turned out much smoother then that. :-) I'm trying candle wax on a peice of oak and sliding it across MDF and yes it slides even better.

makes me wonder... is there already a candle wax extruder? would be nice if we could print candlewax figures, some kind of extruder tube that can be loaded with wax pellets. pull the rope out of a candle grind or shave it into little pellets load a tube and print... Feed the pellets with a drill bit turning in reverse.

What a wonderful idea to print candle wax (or wax)
Hell! you have me going again, I must stop thinking about that straight away ha..ha..

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[regpye.com.au]
"Experience is the mother of all knowledge." --Leonardo da Vinci