Goodbye Marlin, hello Repetier!

I've been struggling with automatic bed levelling ever since I got my Z probe set up. The probe itself works really well, and my printer is calibrated as well as I can manage. When printing without the Z probe, I get quite nice prints. Occasionally I need to move the endstop calibration around 0.05mm, due to the printer heating up or cooling down, but mostly it has no issues with first layer adhesion.

I thought that adding a Z probe would sort out having to fiddle with the endstop calibration every few days, and it sort of worked. However the only Z probe method that Marlin has is mesh based, and for some reason it often gets it wrong. After dozens of prints it was obvious that mesh levelling was getting the bed height wrong in one part of the bed. I've no idea why, it shouldn't be doing that.

All I want is for the software to re-measure the bed position in 3 points, translate the new bed plane into software, and use that. Can Marlin do that simple operation? Noooooo....

After looking through the software, and making some halfhearted attempts to get 3 point levelling working on a delta, I thought I'd try Repetier.


What a revelation! It supports 3 point bed levelling out of the box. After a couple of hours of setup, my printer is now printing totally hands off. The bed levelling routine is faster (due to only having to probe 3 points) and it's way more accurate. There aren't any loose adhesion spots any more, and even if there were, you can manually adjust probe offsets for the three points. And even if the bed has humps and dips in it you can program those in as well. Even without any of that manual fudging, the first layer is now coming out perfectly. I don't have to watch it doing the first layer any more -- just press print, watch the skirt starting, grab the extra little bit of snot that gets dragged around so that it doesn't get hung up on a more important part of the print, and walk away.

One of the best features is something called "babystepping". Basically when the printer is laying down the skirt for the first layer, you can adjust the Z height in increments of 0.01mm. This is brilliant. If, for some reason, your Z height is a bit off that day, you just twist a knob as it's printing, and get a perfect first layer.
You can also adjust all the eeprom settings via the repetier host computer interface, which is really nice.


There are way more good features than I can mention here, but suffice to say: if you are using RAMPS on a delta with Marlin, give Repetier a go. You'll be much happier.

I did just the same last week and had the same experience: Repetier is much less fussy than the RC Marlin I was running.

All my printing is done from SD card and to be able to adjust most important settings with the LCD menu is much easier.
Writing directly to EEPROM is great too: no more compiling over and over while calibrating!

The reason for me to switch was similar: make slight adjustments to Z height on the fly to correct day-to-day variance (or after changing hot-end/nozzle for example).

What I didn't find yet was how to change Z height permanently: babystepping helps for this print, but after a power cycle it's back to the way it was right?
There is also a menu to set XYZ offsets, which suggests these will survive a power cycle but I wasn't able to confirm that.

The documentation seems to be lacking a bit in this respect.

I'm not sure about that if you're not using a Z sensor, I hunted through the menus but like you couldn't see anything that looked like it would do the job. Marlin does allow setting the Z offset from the menu.

There is an eeprom setting in Repetier that lets you set the Z probe height which does persist over power cycles, but that only helps you if you're using a Z probe. I would definitely like to see a menu option to allow you to change the Z height easily from the menu. I'm sure there's a way.

My experience on my delta with Rich Cattels marlin fork has been nothing but fantastic, auto levelling works well and autocalibration was easy to do. Prints have been excellent since using it. It does not have babystepping which I've used on marlin rc3 on my corexy. Very useful but it should save the offset with an m500 after babystepping.

I think the issue is babystepping sends some extra steps to the controller and moves the z axis directly, but its not running within the standard program for axis movement so it doesn't save any data, it's an electronic version of a manual z trim.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I have a Z probe but I don't use it for day to day printing, I used it for auto calibration.
Now it seems more easy to just attach a test indicator to the hotend and calibrate manually (I never thought I'd say that :-).

Currently I set the 'Z max length' with M206 so I have the right distance from nozzle to bed for the first layer.

So babystepping is per print.. I find that a bit odd: if you adjust the height for one print, wouldn't you want the same result for the ones after that?

What do the XYZ offsets found in the menu do? Are they axis or endstop offsets, and are they persistent?

These settings aren't in the documentation which seems rather outdated (https://www.repetier.com/w/wp-content/uploads/2013/12/repetier_fw_user_interface.pdf).
Repetier.com including its forums don't help much either.

Does anyone know of more recent documentation?

I dont know about Repetier firmware as I haven't used it but the z offset in Marlin menu is persistent if you "save settings" or send m500. I think the idea behind babystepping was not to correct huge +/- 0.2mm incorrect gap between nozzle and bed more to trim it a little, but I agree wholeheartedly, its being able to save it that makes it twice as useful as it is now.

---

Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I also switched from Marlin to Repetier, however, I had a few issues (http://forums.reprap.org/read.php?267,655768) which I solved by switching back to Marlin.
One thing I really miss in Repetier is the ability to print really slow, e.g. for small structures which otherwise get too hot. Repetier has a minimum speed calculated from the acceleration. This minimum speed is quite high when working with sensible accelerations.

Next step will be , goodbye repetier, Hello reprap Firmware and 32 bit hardware and then there will be no turning back, specially for a delta

People keep saying that: 32 bit for a Delta, everything else is deprecated or a waste of time. In my opinion, 8 bit and 16 MHz RISC (= 16 MIPS!) and all the nice periphery (e.g. 16 bit timers with variable COMP-buffers) is more than enough for a delta when hosting a nicely done firmware. At least when I am printing with decent speed (< 150 mm/s). Or did I miss something?

Quote
ribaldos
People keep saying that: 32 bit for a Delta, everything else is deprecated or a waste of time. In my opinion, 8 bit and 16 MHz RISC (= 16 MIPS!) and all the nice periphery (e.g. 16 bit timers with variable COMP-buffers) is more than enough for a delta when hosting a nicely done firmware. At least when I am printing with decent speed (< 150 mm/s). Or did I miss something?

Well some ppl like to have something else than 1/16... also add to that a screen and other things like web interface, auto calibration routine and more and a 8 bit is getting tight, also your movement speed must be higher than 150... mine is only 230 and I did not even start to push it, also add more in deep delta calculation because now they have the cpu to run it, think like curve I think.

In a couple year really soon , nobody gonna be 8 bit even the cartesian, there nothing new coming to 8 bit, there just no space anymore for innovation and there more and more 32 bit board option around and. When you build a new delta and have to chose a board there really no point in getting a 8 bit anymore. When you can get a 32bit complete board for what 70$