Geeetech

Hello everyone.
My adventures began last October when I bought from eBay a Prusa I3 Aluminum kit. Assembly was reasonably easy, there was a minimum of filing and shaping required, and the instructions combined with the referenced videos were very good. I got it together in a few hours, fired it up and noticed the X-axis was running backwards. The instructions warned about this, and showed how to change the firmware settings. I downloaded the firmware, made the corrections and, attempted being the operative word, tried to load the firmware. No can do. I got some sort of timeout errror no matter what I tried. I have a couple of older forum posts on the topic, but whist awaiting a reply, I just rewired the X stepper motor. Problem inelegantly solved.

Next, I loaded some ABS filament and a test program made on Sketchup and thought now I'd be printing perfect parts in no time. Wrong! First off, I knew nothing about 3D printing, and ignorance is always a hindrance. I read where 110 degrees for the hotbed was a good place to start for ABS....but it would go no further than 80-85 tops after two hours. Not good. I threw a multimeter on the power supply and found that under load, it put out a whopping 7 volts. I'm no genius, but I surmised that 7 volts wasn't going to cut it for a 12 volt part. I turned the gain pot up all the way and managed to get 9 volts and 90 degrees on the hotbed thermistor. I swapped in a 30 amp 12 volt power supply from my CNC mill and solved the heating problem...110 degrees in about 7 minutes and a steady 240 degrees on the extruder. Great! Back in business!

Next, I managed to booger up the cheap extruder somehow right off the bat. In Geeetech's defense, it was most likely my fault, although to this day I don't know just what I did wrong. Discouraged, I set the printer aside for a few months and got back to it after Christmas. A new all-metal MK8 extruder from Newegg fixed the extruder issue.

Try again: ABS 110 degree bed, 240 degree extruder. Now the ABS wouldn't stick to the glass. Tried ABS juice. Messy and stinky, but some improvement, especially for smaller parts. Adding a brim helped some. More research (Google is your friend!) indicated that PEI is a good base for ABS prints, so I ordered a sheet with adhesive from Amazon, installed it on the glass plate, and now they stick like glue....maybe a little too well.

Now it is mid January, and I am starting to get some recognizable parts...not great, but at least recognizable. The layer lines are very pronounced, giving everything a wrinkled appearance. Playing with the temps and whatnot could make it worse, but not better. More research implicated the pronounced Z-wobble caused by the Z-axis screws not being centered on the servos pulling the extruder laterally in random directions. It turns out a fella had the same problem and designed a set of thingamabobs and put it on Thingiverse. That solved the problem. I printed and installed them and the improvement was dramatic! Better and better.

Next problem was bed-leveling. I discovered the glass had a slight bulge (about .01") in the middle, so the traditional bed-leveling with a sheet of paper was a crap-shoot at best. Also, to avoid damaging the carriage, I took to unclipping the glass and removing it to allow easier removal of the firmly adhered ABS parts. That necessitated releveling by guess and luck for each new print. It would take 15 to 20 minutes to get the bed adjustments compromised until I could get the print started. What a PITA. Enter BL-Touch bed leveling. Naturally, it wouldn't be quite THAT easy. The stock control board wouldn't cut it, as there are apparently no connections for the servo part of the sensor (correct me if I'm wrong). I ordered a GT2560 board and downloaded the Marlin_GT2560-PI3_Pro_B firmware. I followed the instructions here: http://reprap.org/wiki/How_to_Add_Auto_ ... er_DIY_Kit, and after a few hits and misses (my fault for not thoroughly reading the instructions) I got it working, installed and adjusted. Added the requisite G29 command to Slic3r and now it works like a charm. Now it is just a matter of switching the printer on, inserting the SD card, selecting "Print from SD" and walking away. The extruder and bed come up to temperatue quickly, the machine homes and maps the bed, and starts printing with no nonsense. Perfect parts every time. Now that little printer just sits and sings quietly to itself printing parts like nature intended.
It was a real learning experience, adventure, and Great Quest all rolled into one, but worth it. (Although there was a few times I considered taking an oxy-acetylene torch to it)

In a nutshell, this is what I had to do to get my printer working:
1. New power supply: $18.96
https://www.amazon.com/gp/product/B00D7 ... UTF8&psc=1

2. New extruder assembly: $30.05
https://www.newegg.com/Product/NewProdu ... 0314141129

3: Z-axis anti-wobble brackets: $0.50
http://www.thingiverse.com/thing:1424358/#files

4. PEI sheet with adhesive: $19.95
https://www.amazon.com/gp/product/B01KG ... UTF8&psc=1

5. GT2560 control board: $54.98
https://www.amazon.com/gp/product/B01N7 ... UTF8&psc=1

6. BL-Touch sensor $44.96
https://www.amazon.com/gp/product/B01FF ... UTF8&psc=1

Total costs:
Printer: $325, delivered.
Add-on parts: $169.4
Total: $494.40

Printer Pros:
A nice, very sturdy, well-built little printer for the money.

Assembly is not too hard; parts are clearly labelled, and instructions/videos are very good.

Nice and quiet when operating.

LCD screen is clear and bright, most-used controls are intuitively placed in the menu, and easily accessible on the LCD screen. SD card printing works flawlessly.

Nice sized printing area.

Hotbed works very well. Includes a boro-silicate glass bed as well. Bravo Geeetech!

Cost is quite reasonable.

Firmware is easily obtained, customizable, open, and free. Bravo Geeetech!

Printer Cons:
My power supply was crap. I should have asked for a replacement. Too late now, but they are pretty cheap to buy on Amazon. (Mine was a 30 amp version, and cost $18.96)
You may not have this problem, but in the event of poor heating perormance, check this part first!

My extruder failed. This may not have been the fault of the part, but it was cheap plastic, and the motor seemed very weak compared to the metal replacement.
Again, this was not an expensive part, $30.05

The stock control board works, more or less, but I was unable to patch the firmware. Shipping a product with a known problem like a reversed servo is just bad form. No excuses.

The Z-axis wobble is just poor engineering. No excuses. It is easily fixed with a very inexpensive add-on part, but still...?

ABS adhesion: This is not Geeetech's fault in any way, and PLA prints fine on the glass. Also, I know that Geeetech is attempting to keep costs down, which I appreciate, but a reference to PEI sheets and links would be appreciated by newbies.

No bed-levelling. Again, not Geeetech's fault, per se, as this would add considerably to the cost. Maybe some information and links in an addendum to the instructions?
Maybe offer as an option?

For any brave soul who has read this far, and thus may be embarking on a similar journey, I'd be happy to help with any specifics as to how I did what I did and got it to work; just reply to this post.

Cheers,
Gary

Awesome

bang wrote:Awesome

My wife came in while I was fighting with the BL-touch sensor (The sound of the Z-steppers rattling because the nozzle had crashed into the bed for the 50th time was unmistakable, as were my curses and howls of frustration). She asked why I was fighting (and losing) against the machine, and I replied that I am too stupid to know when I am getting in over my head, and too stubborn to quit once I get started.

Seriously, it was a great learning experience, I have a great running printer for just shy of $500, and I have a MUCH greater understanding of how they work, are constructed, and are controlled than I would have gotten from a turn-key unit (if such exists), and can buy a lot of filament with the money saved. I am very happy with the printer at this point.

Yep,the experience is so precious.
Maybe you can post some nice works you have printed.

Wow! Tempus fugit....
It's been about a year, and many rolls of filament since my last post.

I have since upgraded the crappy z-axis steppers and screws with a new set using the T8-2 acme-thread leadscrews, integral to the motors. A more powerful 1.5 amp z motor on each screw necessitated adjusting the Z-axis driver current limit and adding extra cooling for it. The old system kept wearing out the nuts in the plastic things I originally printed to alleviate the z-axis lateral wobble, and I got tired of messing with it. I also rewired it for a remote control-box so that I could add a heated enclosure around the printer for better ABS prints. A PID controller and a small, 200 watt heater, set to 117 F at the print-bed level completely solved the layer adhesion problem some larger prints would occasionally present. I am working on adding a filament runout sensor hooked to the unused X-max pin on the GT2560; I'll update again when that quest is fulfilled.

All in all, I'm still happy with the printer, considering it's low initial cost. It took a lot of upgrades, but now, it's as close to a turn-key ABS printer as one is likely to find for any amount. Next on the agenda: Polycarbonate printing. That oughta be a hoot....LOL

Sounds a lot like my journey with the I3 aluminium so far.

I bought it because... well big fat aluminium frame, hell of a lot better than acrylic or MDF.

Honestly I have no issues with Z-wobble and the leadscrews, maybe I just got lucky.
The hot-end however, holy hell that MK8 is a load of crap. After replacing the heatbreak twice in two weeks I junked it and bought an E3Dv6 that I managed to jerry rig to the extruder. Then a month later I junked that too and splurged on a Titan, no regrets whatsoever.

The control board... Sanguinololu... Just thinking about it is going to give me nightmares for years to come. It works fine for the printer as-is I suppose but Why would anyone want to use the latest version of marlin or change anything in the firmware, right? Holy crap I hate it so much. I bought a GT2560 last year but had to temporarily retire the 3d printer until now. Now I finally have the 2560 set up with DRV8825 at 1/32 (Geeetech, WHY THE HELL do my 8825's not work at all with 3 jumpers set when it works on every other board I've seen?). And at the moment I'm working through some teething issues with my new 3dtouch. It seems to randomly stop working and refuse to home, just dropping/retracting the pin repeatedly and moving up a few mm then refusing to move down until I've disconnected repetier and powercycled a few times, maybe do an auto-home from the LCD... the procedure changes each time it happens.

Got to say, I think Geeetech makes some decent stuff for the money but it can be a real hassle. Kudos to you for going balls-deep and using ABS as a newbie printer, NOT the easiest filament to work with. I've very happily using PETG at the moment.

@Flintlocke,
I agree. The original Snaguinololu board worked, but that was about all that could be said for it. Changing the firmware was my first hurdle, as I recall. I was unsuccessful, LOL.
Aside from the cheap extruder and the sub-par Z-axis screw assemblies, it is a solid little printer for the money, and makes a good base to start from, provided one is comfortable with google, grease, sweat, and trial-and-error. I wouldn't trade the experience for a million bucks (Well.maybe I would), but I wouldn't be willing to do it over again for another million.

JohnDeere630 wrote: ↑

Tue Jul 17, 2018 1:36 am

@Flintlocke,
I agree. The original Snaguinololu board worked, but that was about all that could be said for it. Changing the firmware was my first hurdle, as I recall. I was unsuccessful, LOL.
Aside from the cheap extruder and the sub-par Z-axis screw assemblies, it is a solid little printer for the money, and makes a good base to start from, provided one is comfortable with google, grease, sweat, and trial-and-error. I wouldn't trade the experience for a million bucks (Well.maybe I would), but I wouldn't be willing to do it over again for another million.

I agree completely, it was a great learning experience and personally I like having a device that you can upgrade yourself and see the improvements along every step of the way. Of course turn-key solutions have an appeal to most but personally I think I would get rather bored after a while if it "just worked" right out of the box.

*Update*
Filament detector is working, and the printer has been upgraded to the latest Marlin firmware, version 1.1.9, which I have attached. Note that Configuration.h and pins_GT2560_REV_A.h have been extensively modified.

To recap; what I did for the filament sensor was to desolder the 2-pin X-max socket on the mainboard, desolder the third hole on the edge of the board, and solder in a 3-pin JST socket. The wires from the sensor had to be rearranged, IIRC. I have a post with more details here: viewtopic.php?f=66&t=60915&p=84462#p84462

The printer has also had this bed-plate added: https://www.amazon.com/dp/B07535Y4LR/ref=biss_dp_t_asn It works beautifully for ABS prints. You can't get them off while the plate is hot, but 10 minutes after shutting the bed heater off, they pop free and are just sitting there. Best $20 I ever spent.

The crowning achievement however, was relocating the SD card socket to a slot on the front of the case's control panel. I originally bought one of the SD extenders on Amazon, and while it sort of worked at first (the card had to be inserted before turning the printer on, as it would not detect a newly inserted card), after a few weeks I started getting weird actions on the printer. Long story short, data from the card was being corrupted.

Apparently, I am the only one that wanted to relocate the SD socket, because there wasn't much useful information on the web. The cheap card extenders with the ribbon cables DON'T work, so don't waste your time and money. I wound up buying this breakout board: https://www.amazon.com/gp/product/B01MY ... e_o01_s00?
and direct-wiring it onto the original socket. Here are some pics: Note that the white wire turned out to be not needed, and I later swapped the red and brown wires so that the red wire is now the 3.3V VCC, and brown is now the D0. I'll also attach the color-coded sketch I drew to keep it all straight. After soldering, I applied a liberal coating of hot glue to protect the joints and keep wires from moving and shorting.

I don't get to these forums very often, so if you see this and need help or more details, PM me, as that will email me that I have a reply. Hope all this helps someone.....

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