Prusa i3 3D printer

[tekkydave]

12 hours ago, Dave_D said:

I'd like to support E3D but you're right, they're expensive, especially when you can get a high quality clone for 25% of the cost. Going to be switching to a bowden extruder in the next few weeks.

Have you tried the Craftware slicer btw? Just trying it at the moment and the print quality looks phenomenal compared to the same print with cura

https://craftunique.com/craftware?gclid=CjwKEAjw8ZzHBRCUwrrV59XinXUSJADSTE5kwtmxEydhix6mn0IhnS64WBad7wvXmWa1KqoKFWouZBoCCefw_wcB

I'll have a look at that later, thanks. Especially as it appears to work on Linux.

[Gina]

Yes, very interesting   I'm currently using Repetier Host and Cura Engine slicer which is working very well but I do want to change over to Linux - thinking of Octoprint.  3D printers are only in user mode ATM but I'm planning to do more on mine before too long.

[Dave_D]

Calibration cube using the Linux version of craftware... everything default apart from layer height, top/bottom thickness and temperatures... can't fault it at all

[Gina]

Nice clean print

[Stub Mandrel]

I'm hoping to make a start on mine this week, maybe today!

[tekkydave]

I fitted the new hotend to the printer yesterday. Just needs connecting up & testing. I also need to relocate the existing extruder to feed the filament until I print a new one. Pics later.

[tekkydave]

All connected up to the Ramps this afternoon. I have updated Marlin with the new servo up/down angles and z-homing works ok. I think I might fit a microswitch without the metal arm removed as the nozzle homes very close to the bed (~1mm).

 

[tekkydave]

I have now set up the correct nozzle-probe offsets in Marlin for the new arrangement and fitted a microswitch with its arm intact. It gives ~8mm z offset which is much better. I also mounted my existing extruder on the Prusa frame using an old print of the x-carriage

I cut and installed the bowden tube and tried my usual 16mm calibration cube. There is obviously some changes to be made to the slicer settings for the bowden setup but it all works. If you compare it with a print done with the direct extruder (left-hand cube) then a lot of the 'ringing' caused by the weight of the x-axis has gone.

I need to sort out the retraction and over-extrusion next. I use 1mm retraction at 25mm/s for direct feed but will probably need more for the bowden. I will be looking to print a more compact extruder unit once I have this setup printing well. I was looking at this one on Thingiverse as it is quite small for a geared unit and has a quick-release mechanism.

 

[Stub Mandrel]

Ta-daa!

Now I have to work up the courage to switch it on.

The only bit missing seems to be the knob for the display unit. I have loads of knobs but I can't find one that fits.

[Dr_Ju_ju]

Get it working & print a knob, there are plenty on Thingiverse...   & don't forget the ty-raps on the Y smooth rods

[Stub Mandrel]

19 minutes ago, Dr_Ju_ju said:

don't forget the ty-raps on the Y smooth rods

Ha! They didn't mention those in the instructions.

I must be honest the engineer in me shudders at the prolific use of zip-ties!

 

Anyway, I switched on, the fans started, the display lit up and it didn't explode.

[Stub Mandrel]

The Z-axis has a problem. It stutters and jerks, it isn't the pololu set for too low a current. I have disconnected the drive shafts and tried each stepper individually, both steppers do the same so they aren't the fault. The problem could be the Pololu as what happens is the stepper randomly stops or reverses direction. I will try making sure everything is seated correctly, it may be a bad connection to the DIR signal. Really annoying as I have some other stepper boards but all my pololus are soldered into projects.

Less serious problem is the extruder seems to be wired backwards -I expected this as although the colours are slightly different the top two wires on the connector appear to be reversed.

[Stub Mandrel]

I've found a report of someone else having this issue and solving with a new pololu. I must have one somewhere!

[Stub Mandrel]

The Pololu came yesterday, so I have done a few test prints and started playing with Cura.

A few false starts and experiments, but I find myself needing two big knobs with M8 threads. Half an hour with Turbocad and Cura,m than an hour and five minutes to printv this, worked first time. I'd say the print is as good as the Dremel 3040D.

+

 

[Dave_D]

The accuracy of this printer never fails to impress me  this is a test section of the cooled camera box i'm (re)making (didn't want to waste filament so produced a section in openscad to test the fit)... got fed up with the shop bought project box i was using, it was too big and heavy. The camera body slides perfectly into the front opening and the 1/4 inch tripod attachment slots into a trough in the bottom of the box. Damn good considering this is only 0.2mm layer, the finished box will be 0.1mm.

It's an Anet A8 (prusa i3 clone) kit btw.

[Stub Mandrel]

Why do people keep asking "but what can you do with it?"

[Gina]

I really don't know what I'd do without a 3D printer!!!

[tekkydave]

I have done the thing I said I would never do and decided to build another 3D Printer .

This will be a CoreXY design and will replace the Prusa once fully working as I don't have the space or need for two printers.

I have started a New Topic to cover the build. In true Reprap style the Prusa will be printing the plastic parts needed for its successor then donating some of itself e.g motors, electronics, hot-end.

Funds are tight so I'm selling stuff off to pay for it. I sold a Sony 18-200mm zoom lens for £105 this week so that will fund the first stage which is all the v-slot required. Anyway I'll describe the rest of the build in the new topic.

 

[Dave_D]

CoreXY eh? looks interesting... think i'll stick with my trusty A8 for a while yet though... just fettled it and voila!

that lip at the bottom is just from the brim tho... no more than 20.02mm in any axis

[Stub Mandrel]

I printed a series of cubes from 5mm to 30mm in 5mm steps.

I noticed that whatever size they were they all had a basic error of about 0.2mm, plus a small error that increased with size.

I think there are two errors that need correcting, first over-extrusion of ~0.1mm on each side  then a small amount to be removed per mm printed.

[Gina]

3D printers will usually print half a nozzle-width large purely due to the geometry.  The other error is purely calibration and corrected in the firmware.

[tekkydave]

A new release of Marlin is available. Finally, the full release of Marlin 1.1.0

[Stub Mandrel]

I have had huge issues with filament stripping, I couldn't print more than 5mm of a complex shape without the filament jamming although simple shapes (with fewer retarctions) were OK.

Turned out I had wrongly adjusted the feed pinch roller, so it was squeezing the filament too hard and damaging it. I slackened the adjustment almost all the way off (still quite firm), just passed 5 hours of one of Ed 209's legs with lots of tree-style supports so touch wood it's OK now.

Interesting that Cura was leaving some parts unsupported, even though they were in mid-air. I use Autodesk Print Studio for the Ultimaker Simple and it seems to work the printer fine.

[Gina]

22 hours ago, tekkydave said:

A new release of Marlin is available. Finally, the full release of Marlin 1.1.0

Any notable improvements Dave?

[tekkydave]

I haven't had time to try it yet. I'm using 1.1.0-RC8 at the moment. I'll let you know once I've tested it.