Trying to to set up an older machine for a local school

[Macboy 0]

Hello there and my apologies if this question is in the wrong place - wasn’t sure where to ask it. I’m a long time Cura user and have had little issue with it but I’m stumped on this one. I’m trying to set up an older non-mainstream printer for a local high school who is willing to switch over to Cura from Repetier. Trouble is I can’t get it set up for some reason. It’s got a small rectangular bed (110 x 220) but when I set it up as such it only prints on the back half of the bed. Like it’s thinking it’s the front half of a 200x200 bed. As a workaround I have been using a 200x200 bed but placing the models only on the front half of the virtual build plate. Any thoughts? Thanks in advance. 

[GregValiant 1,409]

Newer printers put the gcode origin at the Home Offset position.  Most rectangular (cartesian) printers have the origin at the left front corner.  A possibility is that the printer you are setting up is an "Origin at Center" machine.  In that case you would need to check the box in Cura's Machine Settings.

When you "Auto-Home" the printer- where does it go(?) and what does the printer display show as the location of the Auto-Home position?

You can open NotePad and put in a short set of commands, save it as a gcode file and print it.  Where the print head ends up will be a telling clue.

G28 ;AutoHome

G1 Z10 F300 ;Move up 

G1 X0 Y0 F3000 ;Move to the XY origin

[Macboy 0]

That’s the other oddity (for my experience) with this printer. It homes to the back right. After homing if I go to move an axis on the LCD the values are all +220 / +110. I cannot exceed those values so they must be flashed to the board? I can however dial down those values which the moves the axis either to the left or forward, whichever the case may be. 

[GregValiant 1,409]

There are a couple of firmware flavors that use G162 to home to maximum. 

 

If the values on the LCD are the max bed size at the home position (in the right rear) then 0,0,0 should be the left front.  That also implies that Origin at Center in the Cura machine settings should not be checked.

A simple gcode file like

G28

G0 Z10 F300

G0 X0 Y0 F3000

G0 X220

G0 Y110

G0 X0

G0 Y0

Should auto-home, move up, move diagonally to the left front, then move to the other three corners and end up back at the left front.

 

[Macboy 0]

Thanks for the help and my apologies for the delay. Haven't had time to get to the machine until now.

 

You are correct on all fronts above. That gcode did exactly as you said it should. I sent the commands one at a time through the Cura Monitor. So if Cura can control it, how do I set up the printer properly without "tricking it" by using a square bed and just setting the models on the front half of it?

[GregValiant 1,409]

You should just have to set up the Cura "Machine Settings" to what you have there.  X(width) and Y(depth) you know to be 220 x 110.  The Z(height) should be apparent.  It's a rectangular bed and "Origin at Center" should not be checked.

Now the Start-Up and End-Gcode could be a little different.  After auto-homing I think I'd want it to raise the Z and go to X0 Y0.  Then heat the hot end and bed separately (if you have the specs on the power supply you might be able to heat them together).  There are some standard settings like G90 for absolute movement and one for setting the printer to metric units.  You would need a G92 E0 to reset the extruder.  If you install an Ender 3 in Cura you can copy the Ending Gcode from it to your printer (using ctrl-c and ctrl-v because there is no right-click menu).

A main setting is the Firmware Flavor as it dictates what commands Cura uses.  I suppose starting with Marlin you would be close.  Since they were using Repetier then the firmware could be RepRap.  Are there any old gcode files around that were sliced for that printer?  They could provide clues.

[Macboy 0]

I had the machine apart to check what board it was using etc as I had given some thought to reflashing with the most current version of Marlin (it's running Marlin currently but I don't know what version). The machine is circa 2018 so I'm betting Marlin is about the same vintage. I still would like to reflash it but was reluctant because I don't really know the finer points of doing so and don't want to brick someone else's machine. It's running a Mega 2560 with a typical reprap smart controller screen.

 

I loaded the code you provided above to an SD card and when I run the file it homes all axis (back right), lowers the Z (it's a stationary gantry printer), moves to 0,0 (front left), then moves to back left and then stops. The LCD readout actually says X2, Y110, Z10. If you see below my bed size info was wrong but I updated it in the gcode before saving to the SD card (x=200, not 220).

 

I'll try to setup the machine again in Cura and report back what I find. I'm also going to setup a simple little 10X10X.5mm block model that I can place in each of the four corners and the bed middle so I can try to get a sense for where it's printing and if it's off, off by how much and in what direction.

 

The original provider did have some documentation but it was very limited. It shipped with Slic3r a config file and instructions to "ensure the bed size is set to 200 X 110mm". When I load that .ini into Slic3r it is pretty limited in terms of info but I can certainly carry those settings into Cura (screenshots attached). I also found some test files the original provider supplied - those are attached also.

4D6_low_poly_elephant.gcode 4D6_machina_calibration_pacman.gcode

[Macboy 0]

Update.

 

So somehow it just automagically worked. The test models seem to have dropped where they needed to be from the SD card print. So maybe you can help me fine tune things? The X and Y min and max values are arbitrarily set at the moment, how do I get those dialled in? I mean I understand the measurements but am not 100% sure if the "distance from nozzle to edge of printhead" means the heater block or the entire assembly including fans, shrouds etc. Also the bed settings vs the actual physical bed area is not accurate. The distance, binder clip to binder clip in the Y is actually 130mm and the width, edge to limit switch is actually 215mm (not a lot to gain there). If we can get the settings where they need to be so we're squeezing every mm out of that tiny print bed then maybe I can ask you to help me reflash to a more current version of Marlin?

[GregValiant 1,409]

Changing firmware is a rabbit hole I don't go down.  Does the mainboard have a bootloader?  How much memory is available for the firmware?  Modern firmware may have a lot more commands enabled and that takes up memory storage on the mainboard.

For now I think working on the basic setup and getting it to print are the main things.

 

That elephant file showed up pretty much in the center of a 200 x 110 printer bed in Cura.  The speeds in the gcode were very conservative.  Retract and Prime speeds were 7mm/sec, print speed at 25mm/sec and the outer-wall speed is 18.5mm/sec.  With modern materials I think you can do better than that but it might come down to how much flow can the hot end deliver.

Retract distance was 1mm.  Is that a Direct Drive printer?

 

The build plate.  This is way easier to describe than it is to explain.

Within the menus on the LCD is there a command for Set Home Offsets?  Is there a command for Save Settings?

Can you move the X and Y to negative locations?  Example:  From X0 Y0 can you use the controls to move the nozzle further to the left and closer to the front of the build plate?

The endstops are likely set in the firmware.  You might be able to shut them off.  If you can't, then wherever you put the Home Offset 0,0,0 (or the Auto-Home 0,0,0 if Home Offsets are un-defined) the build plate will still be 200 x 110 from that location.  You may be able to move the printable area, but not make it bigger.

The first thing - How far to the left can you get the nozzle to go, and how far to the front (remembering to not crash into the clips) can you get it to go?