Prusa i3 3D printer

[tekkydave]

I uploaded earlier and doing some basic testing. G28 & G29 work as expected. However when I try to lower the z axis with G1 Z1 F3600 it stalls. I reset and tried G1 Z1 F60 (lower speed) and it works ok.

The weird thing is it seems to interpret the Fnnnn (move speed) as mm/min for X and Y axis moves and mm/sec for Z axis moves. I need to work out where this is set. If I try to move all 3 axes together with G1 Xnnn Ynnn Znnn the speed seems to be random.

[Gina]

Firmware uploaded and now trying a print run.

[Gina]

I uploaded earlier and doing some basic testing. G28 & G29 work as expected. However when I try to lower the z axis with G1 Z1 F3600 it stalls. I reset and tried G1 Z1 F60 (lower speed) and it works ok.

The weird thing is it seems to interpret the Fnnnn (move speed) as mm/min for X and Y axis moves and mm/sec for Z axis moves. I need to work out where this is set. If I try to move all 3 axes together with G1 Xnnn Ynnn Znnn the speed seems to be random.

Still bugs then.  Seems we are at the "cutting edge"   Not unusual for me!

[tekkydave]

Not sure. Maybe I dont understand the way the G1 g-code works.

[Gina]

I use G0 though G0 and G1 are supposed to be the same.  But mostly I use the LCD menu for manual moves - G-codes in the slicer though and sometimes from Repetier Host.

[Gina]

Servo isn't working right with new version   Wrong angles.  Setting #define NUM_SERVOS 1  fixed it.

[Gina]

Z printing position still about 1mm too much.  The Z drive does change the Z position from 7mm to 6mm though so the drive is working but the amount is wrong.  LCD displays Z position as 0.5mm as correct for 0.5mm layer height so Marlin thinks it's done its stuff.

I guess this must be something to do with my new Z drive as changing the drive appears to have caused it.  As such I guess it isn't relevant in this thread.

[tekkydave]

I have upped the current of my Z stepper driver to cope with 3600 mm/min z axis moves. If it blows up I have some spares !!! Having a go at a test print.

[tekkydave]

Printing my test circle ok now. It makes a lot of noise when dropping the z axis to zero to start but it's not skipping or slipping. Maybe it needs to be that fast but it seems high for the z axis.

Anyway RC2 seems to fix the ABL so I'll stick with it for now.

[Gina]

LCD displays the Marlin version after uploading now 

[tekkydave]

That's a new feature. Quite nice isn't it.

[Gina]

Yes.

[tekkydave]

I have added the following into my start g-code in Slic3r to lower the hot-end for the first layer prior to starting the print at a sensible speed

G1 Z0.35 F60

[tekkydave]

Test print completed ok. I'll post some pics later, got to do some work in the garden now....

[Gina]

See you later then   For your previous post - good thinking

[Gina]

The new Marlin HAS fixed my problem - it's now responding properly to the Z offset value   Just running a test print which is looking good.

[tekkydave]

One apple tree well and truly pruned

I have put some lithium grease on the 5mm threaded rods that drive the z axis and it seems a bit smoother. It still doesnt like being driven at 60mm/s though. It manages it but very noisily.

Anyway here are some pics of my test print. It should be a 170mm circle 2mm wide by 1mm high. Measuring with micrometer shows width from 2.28 to 2.48mm and height 1.14 to 1.30mm. Probably needs to be higher to get a more accurate measurement. My first layer is 0.35mm and subsequent layers 0.25mm so height will be 0.35 + N x 0.25 where N is number of layers. The height will be varying due to bed not being perfectly level but the ABL is compensating as the z motors are moving to compensate.

[Lonestar70]

Hi Gina,

Have you seen this it is quite something.

http://www.ted.com/talks/joe_desimone_what_if_3d_printing_was_25x_faster

Looks like things are going to change rapidly in the 3D printing field.

Keep Happy.

Sandy.

[Gina]

Very interesting - thanks Sandy

[mapstar]

Very impressive Video, thanks for posting the link 

[tekkydave]

The z axis speed problem may have been there all the time but I never noticed. Before I set up ABL the nozzle would only have been a few mm above the bed after homing so the initial move to the first layer would not have stalled.

Now, after the G29 ABL has completed it is about 28mm above. The G1 Z0.35 F3600 stalls because due to the built-in acceleration in marlin after a few mm it is pushing the hardware too fast. Marlin should limit this via the line:

#define DEFAULT_MAX_FEEDRATE          {100, 100, 5, 25}    // (mm/sec)

to 5mm/sec for Z but it obviously isnt. Unless 5mm/s is too fast - it homes ok at 3mm/s. It can be set in g-code using M203 so I'll try that tomorrow.

[tekkydave]

Hi Gina,

Have you seen this it is quite something.

http://www.ted.com/talks/joe_desimone_what_if_3d_printing_was_25x_faster

Looks like things are going to change rapidly in the 3D printing field.

Keep Happy.

Sandy.

Thanks Sandy, fascinating video.

Dave

[tekkydave]

Fixed the problem with z movement being too fast. 5mm/s was too fast as the in Marlin. Now set to 3.3 (= 200mm/min) and working ok.

[tekkydave]

Found an interesting "feature" of Pronterface which can catch you out if not careful. You can set up Macros to run one or more commands and create a custom button to call the macro. There is also a box to manually send commands to the printer e.g. G28. What I didn't realise is you can also type in the name of a Macro and it will execute it. I created a Macro to run the G28 command and called it 'G28'. The macro just contained one command: G28. When I typed G28 into the command box it ran the Macro which called G28 which ran the macro which called G28 etc etc so it ended up in an infinite loop and crashed. So if you create any macros in Pronterface give them sensible names e.g. 'HomeAll' and not an existing G-code name.

[tekkydave]

Everything working ok now. I have also turned down the current on the z motor driver to just above the point where 3.3mm/s runs smoothly.

Trying 3x3 grid points for ABL now as mine seems to be slightly off in the front-right side of the bed.