Solved Print head too far from bed

Hello everyone, just received my Robo 3d R1 and am very much looking forward to being a part of the community here. That being said, I'm having some trouble I do not know how to resolve, and cannot find much via google to solve it.

Basically, the print head is extruding at least 50mm above the bed.
I tried to use the auto level function but when configuring, the print head only gets to about 20mm away from the bed and starts prompting that I cannot go any lower. My first thought was the software, so I tried to use Repetier to print and it was doing the same thing. I also manually lowered the Z axis nuts to the distance I needed from the bed, but the same problem occurred. Any help provided will be greatly appreciated.

Also, I updated the MC software and the firmware, and now I do not have the auto level option anymore. Was this intentionally removed?

 

The auto level in the program was an old throwback, not to be used with the newer printers. There is auto leveling in the hardware of the new printers, and using the one in the software along with it would cause problems. It should always be unchecked.

Sometimes there is trouble with the Z axis when the machine is brand new, at least there was with mine.

I got mine working by unplugging the machine power and USB cord, then manually turning each threaded rod until the carriage was close to level and almost touching the glass. Then I plugged it back in and started it up.

The default Start G-Code is a little wonky with the auto level, but you can get around that initially by preheating the bed and extruded to their target temperature before starting a print. Give this a try and see if you can get an initial print to succeed.

 

Thanks for the help! I just printed a 20mm calibration cube that is dead on, checked on all sides with a caliper. Definitely didn't lower the z axis enough, and I think skipping the auto level sealed the deal as it seems to be causing the print head to move up too much before printing. Also, great to know the old auto level wasn't meant to function with the new printer. It all makes so much sense now.

 

well... you can potentially skip the autolevel if you're lucky in your bed level (which will change with use) and you're printing a thick enough first layer. If you skip auto level permanently you can measure your z offset and use a raft to print... otherwise you'll be stuck with fat first layers and potential problems.
the G29 works well, but the x axis has to be level.
I had similar problems with my first R3d... it also wouldn't advance past a few layers before the Z axis just stopped. It was all likely a problem with the x axis being out of level.

 

My initials checks indicate it's level, but I highly doubt it's 100% accurate. Getting my caliper in there to measure is pretty awkward. Even the slightest angle could make an impact on something so precise. Should be much simpler once I pick up a smaller one. My caliper works fine on my open design Prusa I3, but it's difficult maneuvering it inside the R3D. Constantly checking my bed level is one of the many reasons I bought this printer so I definitely plan on getting the auto leveling dialed in. Thanks for the input.

 

Making sure the X axis is level with a piece of paper is more than enough. You can use a dial gauge to level as well but not necessary.

 

so your method is just to slide the carriage back and forth at say... whatever.. z+.5 and raise or lower it as it drags?

 

I honestly just assumed the auto leveling would accommodate for the initial offset. That, combined with the issues I had with the incompatible auto level configuring in the old software had me convinced something bigger was wrong with my unit. If you read my post in the introduction section, I'm sure this reasoning will make sense. For now, I've resorted to my old way of manually turning the threaded rods during the first layer to dial in the extruder height. Printing a spool holder now. About halfway through and it looks spot on. I'm already loving the R3D. Thanks for the input, everyone!

 

No autolevel can account for Z_offset. Every autolevel routine on any CNC machine requires it. Some can calculate the offset using a particular probe point but that's complex and adds a great deal of cost.

And yes defender, have the carriage around 1 papers width above the printer so you can slide it back and forth without it changing that height. This improves the reliability and accuracy of the autolevel sensors so you get more reliable results. A lot of people will allow their axis to get way off level then be confused as to why it's so inaccurate.

 

yea.. i've been that confused guy..

So what is my Z offset? I was figuring that it was basically the distance the carriage moves to make the switch click on the Z limit. It doesn't seem to change with nozzle or anything. mine is about 1.2

 

You and everyone else without experience in CNC (apparently).
I guess I have used this same principle back in the "old days" when I was taking machine processes etc in college.. 0 wasn't ever 0.

So.. you don't "NEED" to mess with your z offset depending on your requirements. They throw 1mm in there. Its "about" 1 mm. If you're not trying to print .1 at 20% layer squish then you'd probably never notice.

 

Correct, on the robo it's the point where the nozzle touches the bed and the limit switches on the coupling nuts drops enough to deactivate (untrigger). This is the sensing point.

On my printer I use a solenoid probe leveling. For me it's when the solenoid touches the bed and the height the nozzle is above the bed. Traditional logic uses my method of autoleveling hence a positive M565 value eg M565 Z0.9. Since the robo3d triggers after the nozzle is touching the bed before the switches activate thus a negative M565 value eg M565 Z-0.9

 

yea, my buddy uses induction leveling. Not only would that not work with my bed... but.. Though he's using a printbot simple metal and all his 'lectronics are on the side.. I would think all the electrons racing around would throw it off. But he says it works gangbusters. I assume he'd end up with a z offset of around zero.

 

Induction probes are really reliable. It's just a simple switch type circuit that activates when the sensor gets a certain distance to metal. It could be zero since the metal probe has an offset, say 4mm sensing distance. But that would require manual calibration.

 

The copy of MC that I loaded into my MAC does not have the auto leveling control that is shown in the guide. A copy that I loaded into another computer (both MACs) does. Shouid it be there? Could this account for my auto level problems?

 

Don't use the Automatic Print Leveling tool. The guide is out of date and matter hackers likes to change things without notifying them.

 

Now that you're printing away, it might be worthwhile to check to see if your extruder is leaking from the top. It seems to be very common with these when new. Mine did, and so have a lot of others lately. It's a LOT easier to take care of early, and it won't start showing symptoms until it gets really bad and becomes a pain to deal with.

Cool everything off and unclip the fan from the front of the extruder, then examine the top of the heater block. If you see ANY melted plastic there, you will need to tighten your hot end. If you don't, the plastic will continue to build, then start getting all over the place!

 

^Thanks for the tip. This is the first I've heard of it. I will definitely be checking this before I print anything else.

The finish spool holders turned out well. The only issue I noticed was a bit of stringing between parts, and a little on the sides as well. Probably just need to speed up the retraction settings.

 

Mike, where did you get your probe?