This build was largely inspired by Alan Richards CoreXY machine. I did change many things but it was his build that got me focused on this type of machine.
I started this build in March/April 2018 and had a working machine by May. Since then I have been printing many parts and working on improvements and add-ons. Originally it had a Z axis with two steel rods and linear bearings at back. I found that to resonate too much and result in Z-axis banding. I updated my build to use wheels on the Z-axis frame and this has worked far better. I get much smoother prints and more reliable layer adhesion.
Currently I am converting it to have a magnetic X carriage based on the V-notch design from Thingiverse. I have enhanced this design to use Micro-Fit 3mm connectors for easy plug-n-play head changes. This was prompted by the desire to add a laser engraver head.
I've marked this build as complete since it is working but I am still adding and changing things so for me it's always a work in progress. Please feel free to ask questions about my experience and this project.
Rather than writing a story I will list in point form some of the attributes or design choices I made. But first some photos:
New X-Carriage parts detail:
Laser engraver head, showing V-mount and single micro-fit 6pin connector. It may be possible to print parts with micro-fit slots built in but in this initial case I just made a larger slot for the whole connector. I had some on hand anyway.
Dual head V-mount. Note I added wings to the side for planned magnetic mount blower bed fans. The embedded magnets will also connect to the 12V power so no connector or loose hanging wires.
Z-sensor servo detail - I initially glued together a bit of aluminum and a micro switch. That's worked fine for 9 months already but I printed a tiny arm to replace it. I just haven't had the heart swap it in yet. Note how under X carriage the main cable bundle is tightly packed. The spacer piece holding the servo is what is being printed in the photo above.
General Parts Overview:
- T-Slot Black Frame pieces from Banggood.com because of price. In general I was very happy with this. A few pieces had small nicks but mostly excellent and arrived with protective film in 1-2 weeks.
- Most GT2 pulleys and belt also ordered on Banggood. Pretty typical cheap and available parts.
- Makerbase Gen-L, TFT32, E3D V6 clones, stepper motors, wheels, nuts and bolts, fans, MK8 clone extruders, power supply, SSR, wire, cable chains ALL ordered on ebay. Most arrived in 2-3 weeks but as usual some sellers never shipped and I had to re-order.
- Aluminum pieces bought from local dealer and cut with a grinder. I intend to replace some of these with PLA parts over time but I didn't have access to a printer at first and so cut/shaped by hand (very inaccurate hand drilled, filed and generally hacked away at).
- GT2 belt for Z-axis was hand sewn and super glued after. I shaved off 8 teeth, overlapped it, stitched with needle and thread between teeth. The Z-motor is tensioned by moving along frame. This seems to be working well.
- The two extruders used to be mounted vertical but I found the PTFE tube flicked around too much and was noisy. So I turned them sideways and mounted spools horizontal and that works better. However, I found they need a cooling fan this way as otherwise the heat from the motors rises into the filament path and causes feed problems due to soft filament. I'm still undecided if I'll keep them horizontal.
- I'm planning to move spools back 10cm and add plexiglass enclosures to keep dry. I have humidity meters I'll install. Spools are mounted on weight scale stress sensors. Eventually I'll get them hooked to the control board and add code for keeping track of actual filament grams used.
- I use a sugar solution brushed on a 3mm tempered glass bed. That's supported by a 3mm aluminum plate with a 240V heating pad stuck underneath. The heating pad is switched by a 25A SSR. That means less power dropped to 12V by PSU and so a smaller and cheaper 15A PSU is used.
- New X-carriage rebuild is almost done. I've added photos. Connector block fits under normal V-magnet mount. I tried epoxy and super glue for this. The super glue bonded much better with PLA+ I used. If I was doing this again I'd scale the carriage pieces by 5% and try annealing the parts in an oven after for better heat resistance. I didn't think of that before starting this time. Maybe later.
- After making the new X carriage with those lever-like belt clamps I found it was not so easy to get the belts in from behind. The solution was to slip a 6mm wide piece of paper in from the front, then slide the belt onto the paper from behind, and pull the paper back thru. It helps bring the belt thru the slot. Works like magic. The clamps work nicely but I think they were for the horizontal carriage rather than vertical. With this paper trick I find it's easy enough.
- The Z carriage sensor/endstop is done with a cheap EMax ES08A servo (~$5 on ebay). It sits under the X carriage and is wired to a servo pin. Marlin can be configured to swing the arm down for sensing Z position. The arm has a tiny 10 cent micro-switch on it. In tests I saw online this was more repeatably accurate than magnetic/capacitive sensors. At first I bought a capacitive sensor but could not get reliable results. The servo and switch method has been rock solid for me.
Here is the connector pin out I used. Just made this up with an eye to saving pin count. I bring out 5V and two servo lines that can also work for PWM purposes. I'll use servo 2.1 for the laser power.
Update - Dual head in use and some comments.
So I have used both laser and dual head now. It works ok but I have some issues to resolve. If you attempt to use micro-fit 3mm connectors for this be sure to properly crimp the wires. I didn't have a crimp tool and decided to solder them instead. This method (besides being more prone to wire breakage) doesn't fit correctly in the housings. So I have problems with connections coming loose. I am getting a crimp tool and will redo them all. In the meantime it does work but I have to monitor and make sure the fan/temp sensors don't cut out and stop the print. That rarely happens but it can. I'd suggest doing it the right way and in that case I think it will be reliable. I had to make small adjustments to my connector bracket to improve insertion. I will re-design as one piece even if not as easy to print - it will match male-female better as gluing pieces makes it hard to get proper alignment during the glue step.
I am going to design and order some small PCBs for the connector back end and X car back side. This will make those connections more reliable. I currently find them a bit flaky. They are just perfboard soldered up all globby. The wires push into the board and with vibration will break over time. Again, suggest using proper PCB and crimped JST/XH connections. I have that in the works now.
Overall it is working well and I have laser engraved various pieces as well as had good prints with the new magnetic X carriage.
Software used: Marlin, Blender, Inkscape, Cura
CoreCube3D - A CoreXY 3D Printer
Building a CoreXY based 3D printer using primarily parts from China on eBay. Large 500mm frame.
- Build License:
- CC - Attribution - CC BY
Reason for this BuildI was thinking of buying a AnyCubic printer and noticed that many parts seemed to be off-the-shelf open source and cheap Chinese parts. After much exploring I decided I would learn a lot and get a much more in depth understanding of printers if I built my own. Plus I could make it bigger and tweak as I like. It's been fun, more work than I expected, but worth it over all.
Qty Part Name Part Link Comments 13 500mm Black T-Slot 2020 https://www.banggood.com/Machifit-500mm-Length-Black-Anod... Link Most frame members 4 600mm Black T-Slot 2020 https://www.banggood.com/Machifit-600mm-Length-Black-Anod... Link Vertical frame struts 2 450mm Black T-Slot 2020 https://www.banggood.com/Machifit-450mm-Length-Black-Anod... Link Bed support cross members 1 400mm Black T-Slot 2020 https://www.banggood.com/Machifit-400mm-Length-Black-Anod... Link Bed support center member 3 500mm Black T-Slot 2040 https://www.banggood.com/Machifit-500mm-Length-Black-Anod... Link X and Y axis members 2 Hammer Nut M5 T-Slot fasteners (100pcs) https://www.banggood.com/100pcs-M5-Hammer-Nut-Nickel-Plat... Link Used heaps of these. Not sure how many but lots. 8 20T GT2 Pulleys https://www.banggood.com/20T-5mm-GT2-Timing-Belt-Idler-Pu... Link Used for both teethed and non-toother, works fine. 2 MK8 Extruder kit (Left and Right) https://www.banggood.com/3D-Printer-MK8-1_75mm-Remote-Ext... Link eBay sellers kept sending right handed but eventually got a matched pair here. 1 GT2 16T 2x drive pulleys and belt https://www.banggood.com/GT2-Pulley-16-Teeth-5mm-Bore-2M-... Link Also got extra pulleys on ebay. 2 400mm T8 Lead screw (2mm pitch) https://www.banggood.com/3D-Printer-T8-12481214mm-400mm-L... Link 2 T8 Bearing Blocks for bottom Z-axis https://www.banggood.com/2PCS-Lead-Screw-Bearing-Bracket-... Link 4 T-Slot Wheels (5pcs) https://www.banggood.com/5Pcs-One-Pack-3D-Printer-Part-PO... Link Total used: 18pcs 2 Eccentric spacers (10pcs) https://www.banggood.com/10pcs-5mm-Bore-Eccentric-Spacers... Link 2 NEMA 17 Stepper motor 12V 26Ncm 0.4A Link Extruder motors 2 E3D Bowden V6 J-head Hotend 1.75/0.4mm Link 3 Geeetech stepper motor Nema17 shaft for 5mm Link 8 Black M6x25mm Chair Furniture Leg Table Leveling Link Corner Feet and Z-axis support 1 30x30CM 750W 220V Silicone Heater Pad Link 1 Cable chain 10x15mm Link 1 Cable Chain 7x7mm Link 1 SSR-25 DA 25A DC/AC 24V-380V Solid State Relay Link 2 12V 5010 Cooling Case Fans Link 1 Sodial(R) Inlet Male Power Socket with Fuse Switch Link 1 MKS TFT Color Touch LCD Link 3 25pcs Solid Cast Aluminum 2020 Corners Link 1 MKS Gen-L 3D Printer Control Board Link 0 Link 0 Link