D-Bot 3D Printer

[Chriske]

As Dave_D says don't use RealFilament, had the same problem, couldn't get rid of stringing either.
And what is the trick with this system to adjust the wheels so the carriage runs smoothly without any play at all...?
 

[tekkydave]

Today I connected up the Ramps for some initial testing. Basic motion seemed to be working fine so I transferred the 200x200mm heated bed from the Prusa. Then I could set up the x endstop position and bed y position to the correct location. Then the z endstop and bed levelling was set up using the usual piece of paper.

The wiring looks a bit messy at the moment but once I've designed and printed an enclosure for all the electronics it will get run tidily via the vslot grooves. The black & orange thing sitting on top is an 80mm fan keeping the stepper drivers cool

I felt confident so went for a first print; the usual 20mm cube. It started well but the corners get more rounded with z height so something not quite right. Maybe acceleration settings?

Side view:

I am very impressed with the Titan extruder. It's so easy to load filament.

 

[Gina]

The Titan extruders are probably the best things I've bought   Well worth the money!  As for filament I'm very impressed with rigid.ink - cost a bit more but what price good consistent printing!

[Stub Mandrel]

15 hours ago, tekkydave said:

felt confident so went for a first print; the usual 20mm cube. It started well but the corners get more rounded with z height so something not quite right. Maybe acceleration settings?

Try reducing extruder temperature, also do you have a cooling fan on the extruder yet?

[tekkydave]

No fan yet but to be fair I didn't on the Prusa either. I'm currently experimenting with parameters.

I mean there is a fan on the hotend but no part cooling fan yet

 

Edited July 4, 2017 by tekkydave

[tekkydave]

Re-sliced using Slic3r instead of Cura and it printed fine. All dimensions are within 0.05mm of 20mm.

 

 

[tekkydave]

Printed some spare belt clamps. These strike me as the weakest item on the printer and most likely to render it inoperative if they broke.

 

[Gina]

1 hour ago, tekkydave said:

Re-sliced using Slic3r instead of Cura and it printed fine. All dimensions are within 0.05mm of 20mm.

 

 

Interesting

[Stub Mandrel]

1 hour ago, tekkydave said:

Re-sliced using Slic3r instead of Cura and it printed fine. All dimensions are within 0.05mm of 20mm.

My guess is slightly different default settings?

Spot the difference and you have found the cause and can correct it.

[tekkydave]

23 hours ago, Stub Mandrel said:

My guess is slightly different default settings?

Spot the difference and you have found the cause and can correct it.

I have matched as many settings as possible but I always feel Cura is doing its own thing behind the scenes. It produces better support structures than Slic3r though

 

[tekkydave]

Finally got round to printing an updated Titan bracket for the DBot. This pushes the extruder out by another 5mm so the front panel screws become accessible without removing the belt clamp.

I also fitted the belt clamps I printed in PLA rather than PETG. The 'grippy' parts printed better on the DBot and grip the belt without relying on just the tie-wraps. I also fitted the low-profile M5 bolts all round.

With everything installed and working I printed up some adapters to re-use the vibration dampers from my old Prusa on the DBot. Remember these?

They cut down the vibration & noise through the desktop by a huge amount.

 

[Gina]

Just one disadvantage I see with your Titan extruder bracket Dave.  The gear on the hobbed shaft is inaccessible,  I use this on my printers to feed filament down into the nozzle once hot, when changing filament.  I find it very convenient in addition to the lever to take the pressure off the pinch wheel.  Inadvertently I obstructed access to mine on my larger printer (also called Titan) and ended up moving the obstruction away from the gear.  Otherwise, good job - coming on nicely.  BTW I'm just about to start building my third 3D printer

[tekkydave]

It is partially accessible but I tend to use the manual extrude button on Octoprint to push the filament through. There's not much scope to turn the extruder to face front due to the geometry of the printer. I am losing about 20mm in Y as it is by using the Titan over the stock DBot extruder which is a bowden. 

Another printer! I wish I had the space

 

[Gina]

Yes, I see your problem with the geometry, Dave.  One advantage of using your own design is that you can increase the frame size to accommodate things like that.  OTOH I can see the benefit of using a tried and tested design.  In my case I'm using experience from building previous printers in my latest build.

[tekkydave]

The Titan has been performing pretty well so far except when I use filament that is a true 3mm diameter. The 2.85mm filaments seem to be ok but 3mm causes the drive to skip steps. I have the tension spring all the way out. I suspect the pancake stepper motor doesn't have enough torque (21Ncm) to push the filament through the hot end. The latest batch of white filament I have bought from WeDo3DPrinting needs to be extruded at 240°C to be fluid enough to go through without skipping. I've checked the stepper driver volts and it is 0.55 which should be correct.

I might try fitting the motor I was using on the Prusa extruder. It's heavier but should give me some more torque (36Ncm).

[tekkydave]

I think I've cured the issue with the Titan and 3mm filament. I replaced the stock tensioner spring with a similar one which I shortened to about 2/3 of its length. I now have a better range of adjustment and can slacken it off far enough so there isn't excessive pressure on 3mm filament. The white filament is now extruding happily at 220.

 

[ZiggyNZ]

On ‎5‎/‎29‎/‎2017 at 19:29, tekkydave said:

Yes, I'm still getting stringing. I need to calibrate the temperature and retraction before I print any more parts. 

Hi Dave. I haven't tried PETG yet, but recently set up an Ultimaker Original +, and am using Cura.  Had lots of issues with stringing (and other gremlins too) with some filament, and found this guide http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide was really handy - seems likely to apply to any printer, and its fixes refer specifically to Cura settings. Cured my stringing problems in the end by enabling retraction, enabling Combing mode, and lowering temperature (190C with the problem PLA).  Found also that it was very filament batch dependant: although this was with PLA from a reputable supplier, their grey performed very differently to other colours which were OK at higher temps.

Will be interested to see how you get on with your open frame!  Let us know how it works out for rigidity. I picked my printer kit in part because I liked the idea of solid-ish walls (plywood, in my case) to get rigidity, and it's easier also to fully enclose the printer to run ABS print jobs, which I'm tending to do when I need "strong".

Looking forward to your updates, and I wish you every success at this.

 

[ZiggyNZ]

On ‎7‎/‎5‎/‎2017 at 06:03, Stub Mandrel said:

My guess is slightly different default settings?

Spot the difference and you have found the cause and can correct it.

The original cubes done with Cura look as though there could be over-extrusion? If so, all the walls would be squished out slightly. If the cube is slightly wider than it's supposed to be on the sides, the effect would be compounded on the corners and they would gradually try and climb up... which is what we see.   Nice to see that you *did* get acceptable cubes in the end.

[tekkydave]

Designed and printed a couple of brackets to mount my ATX power supply on the V-slot frame. I will need to add another cross piece at the bottom level to bridge across to. I now need to design an enclosure for the electronics in a similar fashion to hold the Ramps, RPi3 plus any other electronics I need to incorporate.

 

I've also bought a piece of ecocast aluminium plate 300x300x6mm to give me a larger print area. I've also ordered a 300x300mm silicone heater (750W @ 220V) and a solid-state relay to interface it to the Ramps o/p. Both on the slow-boat from China so will take a few weeks to arrive.

[Gina]

The heater should give you a quick warm-up   I find a 300W 24v heater on my Titan 300mm square bed takes about 3-4m to heat from 20°C to 100°C.   I have a 1200W 220v Lenovo heater for my 400mm square bed which I'm looking forward to trying in my bigger than BIG 3D printer under construction   I think I may re-adopt the name Giant for this over 400mm cube build volume printer as it will be using many of the parts I bought and made for my original and abandoned, Giant printer project.

[tekkydave]

Your description just reminded me of the Tom Hanks film 'BIG'

Maybe you should call it 'Hanks' or 'Tom'

 

[Mick J]

The neatest ever computer psu power supply just got pretty !!  love the blue surround 

[tekkydave]

Well thank you for saying so

 

[tekkydave]

The Silicone Heater I ordered has arrived. I made the mistake of buying a metal base 300x300x6mm so leaving no room for the mounting screws. I have managed to snip approx 6mm diagonally from each corner of the heater to clear some space. I could just see where the wires were inside the heater and I had my DVM connected measuring resistance but it was heart-in-mouth time whilst cutting 

Next job is to drill and countersink 3mm holes at each corner for the mounting screws.

[tekkydave]

A couple of pics:

I would strongly advise anyone doing something similar to get a slightly oversized plate, e.g. 310x310mm or 320x320mm to make life easier.