Greg's SmartRap Build

not had a chance to try the camping gas stove yet as now on holiday for 3 weeks .... Will try for an update when I get back.... Happy holidays to you all!!

Try to make some sandcastles 3D style and bring some innovation to the beach.

Happy holidays !

Hi Zackary,
I am not sure if you got the levelling issue and fan issue figured out due to your hot end problems but i know one thing that wasn't clear to me in the beginning was that the Gcode commands for G29 (3 point probe) and also the Fan ON/Off functions need to be added into the Slic3r custom code to have any effect on your prints.

If you use the manual instruction to set the fan to On in Repetier then the Slic3r code will override that code when you start a build. Same for the probing, unless it probes as part of the build code then the G29 will not take notice of the probe measurements.

In the Slic3r configuration you can enter a string of commands which will become part of every build file, thats where the G29 should be added and any fan instructions.

Regards
Mike

Hi Guys
It's been a while but did not want to update on progress until I had some clear results, today I spent the whole day with the printer.
If you remember I have 2 problems:
1. it doesn't extrude enough PLA giving nasty prints as shown earlier.
2. I can't get the first layers to print without the hot end dragging across the bed - I suspect I am setting Z wrong.
So far I have:
1. Straightened the PLA bowden support with a hair dryer (mentioned above).
2. Dismantled the hot end and burnt off excess PLA with a camping gas stove and re-assembled.
3. Obtained some replacement PLA bowden supports just in case.
4. Replaced the Z axis coupling that disintegrated with the latest cone shaped Z motor connector from a more recent design.
Tried printing and no difference - very, ver frustrating, however the z axis stop is a lot smoother now I have re-routed all the cabling..

After I stopped looking at PRUSA printers ;-S , I removed the Bowden tube to measure how much PLA the extruder was actually pushing through.
With hot end and bowden tube removed I found that whilst 10 and 20mm extrudes OKish, when I try to extrude 100mm manually from Repetier host, I only see about 60 mm come out.
I can see the gear turning but the bearing is slipping.
I removed the bearing and added one layer finely cut masking tape to it's circumference and slipping is down to 80mm for a 100mm manual extrusion - will try another layer next weekend.
I know this is not a great fix but I hope it can hold to enable me to re-print parts for the printer.

.

I have a few questions on Z off-set that I hope you can help with.
I am following this process:
1. Home x, y and z.
2. Run G29 (3 point probe) and Repetier Host shows:
< 00:02:33: Bed x: 10.00 y: 10.00 z: 6.16
< 00:02:38: Bed x: 10.00 y: 140.00 z: 6.17
< 00:02:43: Bed x: 100.00 y: 70.00 z: 6.73
< 00:02:43: echo:endstops hit: Z:6.73

3. At the last G29 probe point, near the center of the front of the bed, I raise Z to get a piece of paper underneath, counting the increments e.g +1.7mm

3. I then check (and don't understand) at the last point how much Z has changed with M114 that provides these numbers in Repetier:
< 00:06:58: X:100.06 Y:70.00 Z:-4.40 E:0.00 Count X: 100.10 Y:70.00 Z:-3.43

4. I then have enterred M555 Z 7.43 (from 6.73+1.7) - (I have been too scared to enter the negative values from M114)
5. Store results with M500.

And the hot end always crashes into the bed and drags with the Z stop triggered during the first part of the print - not good I'm sure.
Am I putting the wrong value in for Z ?
What value should I be enterring?

Many thanks for any suggestions,

Greg

Last minute thought:
From the value from the G29 origin z=6.16 to the value at the last G29 probe at the front of the bed z= -4.4, this would provide a difference in bed level of 10.16mm.
I have checked the bed to the workbench with a ruler and at best I can see 2mm difference nothing like 10mm shown in the software.

Apologies just saw mikefiatx19 comments and hadn't realized that the manual commands are overwritten by the Custom G-code - fixed the cooling issue there but not sure how that may affect G29 and Z off-set ...

Edited 1 time(s). Last edit at 10/12/2014 06:44PM by zackary.

Quick question, with the hot-end raised (and cold, heh), if you run your finger across the nozzle does it move back and forth much?

I had the same issue as you with being a total newbie to all this and making a mess of my huxley support bar ... fortunately, the hair dryer trick worked very well and everything is ok now, but one of the things I had to ensure was that the bars holding the screws in were re-formed too, as otherwise they'd only provide a loose hold on the bar. The result was that the nozzle would get dragged out of position and I wouldn't be able to print well.

Tiny thing, thought I'd suggest it because I had the same issue with the support bar. I too am a total newbie, and reading your ride seems very similar to the one I went through! Actually, I think I'll start a "mrmillsy's build" thread, heh

Finally, regarding the Zhoming, this is the (NEWBIE!) process I use, which has provided a couple of successful prints:

Home X,Y
G29
Raise Z until I can get paper underneath, lower Z by 0.01 units until the paper can move around with a little bit of friction -- makes it hard to get paper in and out, but can manage it JUST. IE, getting it to the minimum distance possible.
Check new number in repetier-host, next to Z. Let's say it's 1.14
M555 Z1.14
M500
-> Slice & Print

Which sounds like I'm really not doing anything LIKE what other people are suggesting, but as I say, it's given me a couple of prints.

Good luck!

Hi,
With regard to the head moving I had a similar thing. I had to perfect the balance of tightning the bolt that holds the moving arm so that it's loose enough to allow the arm to move, click the switch and then drop back down. But not so loose that it wobbles when its printing. It's a balancing act that you will get if you try a bit. In the end i used a nyloc bolt with the nylon ring inside to lock it in place.
Re your probe points, watch how the nozzle moves when you start a print, does it look like it's leaving the plane of the bed by 6 mm?
Re the g29, you lost me a bit in what you said above.
It baffled me in the beginning when I started and I found info difficult to piece together. Basically, i put the G29 code into the slicer custom startup code, make sure G29 is in there after G28 and then i gave printing a go with the z off set at 0. It started to print with the nozzle in the bed. I switched the offset to z2 and tried again. That was printing in the air. I tried again at z1 and it worked great so i left it there.
I suppose next time I might mess around with the paper and counting the z distance but i never really knew what I was doing first time round and it was easy. I do find that some times the nozzle will be slightly closer or further away from 1 print to another but i think thats just some kind of weird factor that I am missing (dirty nozzle maybe).
And like I said before, you can manually do what you want before you run a print job but when you start a job the printer forgets everything you already typed and uses the slicer Gcode for the build so other that the eeprom commands (m555 z*) you are wasting your time with the homing manual G29 commands.
Regards

Edited 1 time(s). Last edit at 10/13/2014 05:50PM by mikefiatx19.

Mr Milsey and Mike fiatx just the advice I needed...thank you!!
I shall try and get the extruding fixed and then give your suggestions a go at the weekend.....

Hi Guys,
i spent another 5 or 6 hours on the printer last Sunday.
I started about 15 or 20 prints just to try and understand what's happening with all sorts of z off sets.

the good news: I have finally understand how to get the start code in Repetier for the G28 and G29 codes and ensuring the fan is on ALL the time. Without manually editimg the G code .... The bad news is that the head seems to arbitrarily decide to dig into the bed or hover 5 mm above the bed and the prints are rubbish. I cancelled all bar one.

I also removed the extruder bearing again and wrapped. 3 total turns of masking tape around the bearing as it appeared to be slipping.
If I measure how much PLA comes out the other side of the extruder motor it,a about 80 % of what I manually request in Repetier ie ask it to extruder 100mm and 85mm is pushed out via the motor. Will measure at the bed this weekend.
The bearing no longer slips constantly but the printing is still rubish.

The only extruder fix i can see is the 4.9.2 design - i shall look to see on github if there is an 8mm rod version.

MrMilley I tried pushing the hot end and it moved very very little .... Less than 1_2mm if pushed hard and this onlY happens when it digs in to the bed.
If I need to re-print I'm thinking of a version upgrade and or change of model.

Edited 3 time(s). Last edit at 10/24/2014 02:31AM by zackary.

Yessss, it's best to connect the hotend cooling fan straight to the Powerline and use the variable fan output to control the fan that blows on the printed object.

It's not just best, it's the way it was meant to be.

sorry for the extruder zackary.. it's still too fragile. I'm redesigning actually to make it more solid. the idler will have two parts so it doesn't bend and the body will have something to prevent it to bend too . Sometimes it works well but after hours printing this model always bend under force + heat.

It's the weak point and that for long time..anoying


you're so right backemf, I realised too late i've used the head fan on the cooling system. so it's always complicated to have it run when we want. If you jsut use repetier or cura as is..it will run only "sometimes" .

best is to plug it on power and uncheck all software fan control. the software is for the part cooling fan .

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Thanks BackEMF i'll have another look at that today... I did check it out before but got confused with so many wires... Let me re-read the previous post at the start of the thread...

Hi Serg, running out of ideas to get it to extrude correctly, I think I need to get to get re-printed the extruder parts... Do you recommend me waiting for the re-design or go with the version 4.9.2??

Thanks

greg

Hi greg,

I can for waiting print you a new extruder parts, it's fast and easy to send.

For the redesign, it will take a few days more i'm affraid. I'm fighting with modelling a good support ( we need a little breakable support to attach the back of the body to the main plate_base to make it more solid.

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Hi Serge,
That's a kind offer .... I think I need to e-build the RepRap completely so will wait for the next design to come out.

Quick update on progress follows where I performed the following activities after re-reading this blog:

1. Turn the printer round for working on - required a longer USB cable that I took off a working HP paper printer. Result: The SmartRap would sent temperature and not respond to any manual movement commands. Went back to the short USB cable supplied with kit and all working. Weird - has anyone else seen this?

2. Checked the free movement of the bowden support against the Z stop. Not too bad but wanted to try a washer so dismounted and placed small washed between bowden support and hot end support. Result: Appeared slightly more rigid Bowden cables appears slightly too short on full x extension but fine to start with, Full x and z could be a problem.

3. An earlier note in this thread was to check for Z wobble -I had not done this since changing the Z coupler to the latest design. Result: Z motor made a lot of noise and vibration and the motor shaft no longer revolves - Z motor appears to be dead. agghhhhhhhhhh and not even one print yet!!!!!! excuse the frustration....

4. Tried pushng the filament through by hand with the motors disabled. Result yes it is stiff but filament does come out in a thin thread.

5. Tried manual extrusion (200mm/sec) using the the motors: first 5mm , then10mm 20mm, 30mm and 50mm.
Result: filament comes out but there are occasional delays and occasional moments when the idler bearing does not rotate.
Filament usually has a slight delay (2-3 secs) before coming out as seen at the end of the video.

6. Next test for zeroing z offset using MadMike, Mr Millsy and Mr Reg Pye's procedures could not be performed due to dead z motor.

7. Tidied up End G Code for better cooling but did not re-wire the fan - this is required but I'm focusing my efforts on getting it to print for now - seeing this as a finishing task at present.

End of tests.

Edited 1 time(s). Last edit at 10/26/2014 01:13PM by zackary.

On the last of the extrusion tests I was shot this video (50mm extrusion) where you can see the bearing slipping .... not much but it does slip.
The extruded filament appears very thin as well .... other videos make it look thicker .....

[youtu.be]

Hi greg, sorry i didn't remember you had an old version.With the integrated extruder without screw, if it doesn't work, it won't work. I will make you a new set if you wnat. It's not normal this way, it should have work long time ago already .

I can't remember if you have fishing lines or rack&pinions ?

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