Thursday, July 2, 2015

eBay "CTC" 3D printer - first impressions

I have been building my own 3D printers for several years now and I'm pretty happy with what I have.

But I have been keeping an eye on what's coming up on eBay recently, and I finally decided I had to get a better look. The one I picked up is a clone of the Makerbot Replicator 2, including dual extruders, for $500 shipped from the US.  I ordered it on a Friday and it arrived in Michigan on the following Wednesday.

TL;DR: Here's a photo album because photos are nice.

This seems to be a very close copy of the Replicator 2 as far as functionality and use goes.  It's made from laser cut plywood, painted black. The electronics is an exact clone of the Makerbot Mightyboard. They are distributing the Makerbot software and drivers.  Two years ago I would have been indignant about such a thing. Right now I don't feel that Makerbot deserves any sympathy whatsoever.

The machine arrived about 98% assembled. The only remaining step (ideally) after removing it from packaging was to use two screws to attach the printhead, four zip ties to attach the filament feed tubes, screw the spool holders on the back and get busy learning the process.

In reality there were some bumps in the road.

The most obvious was that there was NOT ONE WORD of instructions printed.  Eventually I found that the included 2GB SD card, besides the software, had a manual, if you can call it that. The manual was in DOCX format - apparently they believe that everyone has a copy of Microsoft Word. I had to download and install about 60 megabytes of Microsoft viewer and compatibility packs to view it. They should distribute this in PDF or HTML form.

The manual is not very good.

If you get one, here's a guide to not breaking the printer in the first 5 minutes:

  • Remove from all packaging.
  • Remove boxes except the ones under the print surface.
  • Remove all of the zip ties holding the motor and carriage from moving, unwrap the extruder (printhead).
  • SLOWLY lift the print surface up. You're spinning a motor when you do this, and that generates electricity which feeds back into the electronics. If you pull motors on a printer around fast, you stand a chance of damaging the electronics.  You can see the LEDs flashing sometimes if you move motors, even with the printer unplugged.
  • Get the boxes out from under the print surface.
  • Attach the printhead to the carriage. I don't think any of the screws I got were the right length. Either too long (bottomed out) or only caught about 3 threads on the aluminum block. I grabbed some M3x10s out of my workshop and they worked fine.

Hardware issues:

  • One printhead was quite a bit (2mm) lower than the other. This made the printer unusable as it was - I had to partially disassemble the extruder and adjust the height on one of the heads until they were even. (see photos below)
  • The spool holders it came with are too large a diameter for many of my spools. I suppose they work just fine with officially licensed and priced spools.
  • They just whack three strips of blue tape over the kapton, with huge gaps, and expect that's how you'll print. It's picking nits but it is kind of weird.
  • The ad said it came with ABS, it actually came with PLA.
  • The instructions don't even mention installation of the flexible feed tubes, and it didn't come with the cable ties required to put them in place.  There was only one feed tube supplied.
  • Several screws were loose. One had fallen out. TIGHTEN THOSE SCREWS.  ALL OF THEM. I missed a few and it bit me in the ass:
  • After a bit of printing, I had an issue where the right extruder was very low again. I disassembled the printhead, it was within 0.02mm of the same height, so that wasn't it. Eventually I discovered that a screw had fallen out on one of the gantry supports on the right and it had sagged a bit.  So tighten those screws to avoid frustration.

The software install was pretty horrible. It's partially in Chinese, has a few random English words, and a lot of just garbage characters. The only recognizable English is the name "Replicatorg" - even the "install" buttons are just Chinese characters. I poked a few things at random and eventually installed Replicatorg.  All of the device driver installs failed (Windows 10). More about the software later.

Here's the biggest major issue with the printer as it came (I figure most people can figure out to tighten screws). As stated above, one printhead was not inserted all the way into the heatsink block properly, so it was impossible to level the printbed properly.

The solution is to remove the fans and heatsinks from the front, then loosen the setscrew holding the hotends in place (they did NOT include a wrench that was the right size for this - one that was close but as far as I can tell does not actually fit anything on the printer) and shove the hotends hard up against the bottom of the extruder body. Once I did this, the tips of the hotend were within 0.01mm of one another by my gauge.

Firmware / printer control:
This is a total rip-off of Makerbot's firmware, so I suppose they should get the blame. The firmware on this printer is just "functional" but not "nice" from the point of view of anyone who is used to Marlin on a RepRap. You can't change printspeed during a print, you can't alter printer parameters (hotend temp, etc) during a print. I suppose I'll live with it, but if there were a build of Marlin that ran on the Mightyboard, I'd be installing it right now.  I might consider it anyway, and maybe even mount a rotary encoder for control.

Heck, I might even rip out the Mightyboard and just cram in a RAMPS board.

Anyway in short, functional, but not very nice.

I quickly found out that the Makerbot firmware can't read a standard GCode file, which is just weird. You have to convert into their goofy format.  ReplicatorG can do it, as can some other software.

Anyway I decided to just try ReplicatorG for a bit, maybe it'll impress me.


Maybe this is some kind of hacked version, but it doesn't seem so.  Apparently Makerbot people actually put up with this.  OMG Replicator is a horrible piece of software. It's straight out of 2011, which is about when dinosaurs roamed the earth in 3D printer terms.  Skeinforge?  Seriously? Who uses friggin' Skeinforge anymore?  It's not 2009.

I also can't change the settings. It takes me into Skeinforge settings, but when I hit "Save All" then exit, the thing is locked up. I had to hard reset my PC to get control back.  Later I found out I could kill python from the task manager and get control.

The software is mostly a pretty shell around some very outdated core functionality, with extra "proprietary file format" stuck on the top for icing.

Since I couldn't do anything to change profiles or anything, even when I told it to use a lower temp it still insisted on using ABS temp of 240 to print (and you can't change temps from the control panel mid-print - very medieval this control panel), it printed way too hot for PLA.  Here's a sample printed from Slic3r (left) and Replicatorg (right) showing what happens when the temp is too hot.  Also showing that it insists on using a friggin RAFT!!!  Seriously, why use a raft unless your print bed is badly warped?

Actually GOOD software:

My recommendation: Use Slic3r.  Generate GCode from that, and then then use the program found here: to convert to the x3g file needed.  A command line for this printer would be as follows:

 (program path)\gpx.exe -g -p -m r2x (sourcefile.gcode) (destfile.x3g)

Personally, I unzipped gpx files into d:\apps\gpx and created the following in the file gpx.bat:
d:\apps\gpx\gpx.exe -g -p -m r2x %1 %1.x3g

Then in Slic3r, go to Print settings / Output options and enter the full path to the BAT file:

You'll also want to go to the "Printer Settings" tab, then under Custom G-code, put in the code from this page:

There's other good stuff on there.  You'll want to create a single left, single right and dual extrusion profile.

One hint I missed at first on Slic3r for this printer:
in Printer Settings, set the print bed to 225x145mm, with the origin at 112x72.  The firmware puts the origin in the MIDDLE of the printbed, which is unlike all other printers I've seen and this really threw me for a while - it kept starting to print on the rear right corner of the print surface.

I always print from SD card. I've had prints fail due to various PC related issues, so I just don't do that anymore.

In the end I managed to get over all the speed bumps and do a dual extruder test print. It took probably 6 or 8 hours of f'ing around though, largely fighting with what I thought was a plastic problem, then I thought was a printer problem, and in the end wound up being a Slic3r bad config file, then had that screw come loose and the gantry collapse a few mm and I thought I had 3 different problems.  After all that, here's the sample. There's a bit of a gap, but that's a setting in Slic3r that I can fix easily:

The printer itself is absolutely amazing for the money. Hardware wise it's far above any of the RepRaps I've built to date. Construction was a bit slipshod, with the loose screws and the misaligned printheads. The PC software is mostly laughable compared to Slic3r or Cura from Ultimachine; but remember, this is Makerbot's software, so even if you bought a Makerbot you'd be running the same regrettable software. If I were paying real money for a printer, I'd buy from Ultimachine any day of the week before Makerbot, from what I've seen here. The firmware is acceptable. There aren't a lot of options, but honestly, few people actually adjust the acceleration curves in the middle of printing, so it's not a huge problem.

I think that anyone buying this as their first printer had really, REALLY better get a mentor. I think a 3D printing newb with no guidance might as well set fire to their money. But honestly, that's almost true of any 3D printer. Even with a modern, proper Ultimachine or Makerbot I think there's a huge learning curve, and without a mentor many people would be driven to distraction.

So: amazing printer, even without adding "for the money" to that. The low price comes with a few problems, but nothing surprising or insurmountable - 30 minutes of fiddling for someone who knows what they're doing. With ANY 3D printer, if you haven't used one before, you NEED to find someone to mentor you, even if it's just online.

All of the software, whether Slic3r or Cura or Replicatorg, have their own learning curve. Design has a curve as well.

It's a hell of a fun hobby, but it's NOT for the impatient.

Photo album:


Tattva said...

FYI, Monoprice is now selling a nearly-identical printer (using laser-cut wood, one extruder) for $300. It may be a sale price for the holidays:

John Ridley said...

Thanks for the pointer.

It is single extruder and no heated bed. And the printer I reviewed here with two extruders and a heated bed is now down to $410 shipped. IMO $110 is cheap for those two features, if you will use them at all.

Honestly, I don't find very much use for a 2nd extruder, though I do use it occasionally.

I DO use the heated bed all the time, even with PLA. Even PLA can warp and unstick from the bed at room temps if you print a large object, heating the bed up just a bit, say to 40, helps a ton with adhesion and stopping the warping. Also it's nice to be able to print ABS for the occasional project that required extra heat resistance.

The $300 printer is pretty amazing, and it'll do just fine for a whole lot of people. If money is a problem it's a very valid choice. The 2nd extruder can probably be added pretty cheaply if it comes to it - you can buy a compatible, ready to rock extruder on eBay for $30. The heated bed, not so much, it's an odd size and they may have used a smaller power supply to save money with no bed.

David Ashley said...

After having it for 6 months how has it held up? Is it actually plywood or mdf? Is the print quality any different than your reprap? I am considering one as a second printer, my first was an mdf i3 that I purchased as a kit.

John Ridley said...

It's been fine. No new complaints have cropped up. I would love to be able to use Marlin or some other firmware with it, the firmware it comes with is Makerbotish and it's really wretched. No PID on the heaters (massive overshoot/undershoot on temps), no dynamic control during a print, etc. Really not a huge deal for just churning stuff out.

It's plywood. Print quality is better than my plywood box-frame i3. The full gantry X/Y movement is more solid. There's still some vibration evident in the print but it's not as much as in the i3.

I'm happy with it as an everyday printer. I'm past the point where I care that much about just playing with printers for their own sake, I just need to print stuff now and this is good for that. In general it just works.

The extruders on this are much better than the Wade's I had on the reprap. I can use 1.75mm TPU (flex) filament just fine. Couldn't use it at all on the RepRap.

Brett said...

Have you tried sailfish firmware ?

Brett said...

Have you tried sailfish firmware?

John Ridley said...

Brett: Yes, see later post. It is an ever so slightly less horrible firmware than what the printer shipped with. It's still pretty wretched compared to Marlin.

Jonas Paaske said...

A few factual errors. Most notably, you claim that replicatorg is makerbot software, which is not the case. Makerbot has an interface called makerware, which is much more user friendly. It used to lack some important settings (unless you wanted to write your bloody profiles in a text editor!), but nowadays it's pretty damn good. And it'll work with the CTC as well. Try it out, maybe write a post?

John Ridley said...

Thanks for the corrections. I have only ever seen Makerbot stuff in passing at Maker Faire, never seen the software running so that's good info.

I might try it, if it works with RepRap and standard GCode, but I was really talking about firmware, not software. The firmware on the CTC, even Sailfish upgraded, is wretched compared to Marlin. Temperature control is abysmal, motion is really bad as well. And the fact that the printer can't consume industry standard GCode is ridiculous.

That's going to require replacing the electronics, but I tried that once and really I'm probably just going to sell or relegate to backup duties the CTC and build a new RepRap printer, where I can get exactly the qualities I want.

Gauthier LE ROUZIC said...

Hi Guy,
I'm trying to find the best print profile for my CTC printer.
I'm using Makerware.
Can you send me your profile on replicator G or makerware if you use it one time?
For now, I have not update the printer firmware.

Thanks for your posts !

John Ridley said...

Sorry, I've never touched Makerware. I'm using Slic3r under Repetier

Gauthier LE ROUZIC said...

hmmm ok :(
Can you send Slic3r and Repetier config?

John Ridley said...

It's already posted in the next article I wrote on the CTC:

Gauthier LE ROUZIC said...

Oh Yeah ! Thanks! I will read it soon! :)

New printer: JGAurora A3

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