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Are all these kits this bad?

Posted by SupraGuy 
Are all these kits this bad?
December 16, 2014 06:31PM
Okay, I bought a Prusa i3 kit a couple of months back.

In short, I'm not too impressed.

When I opened the box, all most of the parts looked great. The rods were nicely sized without sharp edges, the threaded rods were well-packaged and straight, the laser-cut acrylic frame for the Z axis looked very nice. One of the Z axis bearing holders looked like it had been printed with a missed step, which was annoying, but not bad enough to preclude assembly.

And so, assembly begins...

Instructions? None. Well, dig around on the website that I ordered from and there's a sort of diagram of how things should be, and a couple of notes regarding belt tension and so forth. I can figure it out from there, I guess.

Issue number 1: While assembling the base, one of the leg parts splits. Well, not TOO bad, I'll just use extra zip-ties to hold the leg together. Once the printer is operational, I'll schedule making new ones, as I have a complete set of object files for it.

Issue number 2: The Y axis clamps for holding the belt are extremely brittle, and attempting to tighten the clamps results in broken parts well before there is actually any tension holding the belts in place. More zip-ties to hold stuff, again, once the printer is functional I can try again.

Issue number 3: The allen key that comes with the kit doesn't fit the set screws for anything. Not for the motors, not for the hot end heater... Nothing. Good thing I have a set.

Issue number 4: holes for the 8mm rods are WAY too small on one side. Drilled out holes in 3 steps in order to make them large enough to hold the rods. Even then I feared that the holder was going to split when I inserted the rods.

Issue number 5: The X axis clamps are no better than the Y axis ones. Even more zip-ties. Good thing I already had some, since the ones provided in the kit were all crap which would break way before any actual tension was on them.

Issue number 6: Not enough screws to actually assemble the kit. Extras of some sizes, not enough of most.

Kit came with a box for the electronics and PSU. Neither actually fit in the box.

No major issues with the rest of assembly, though making sure that things were at correct right angles was a major pain. All too easy to skew the X axis off square from the Y axis, and the acrylic frame isn't the best way to keep the Z axis square to the X/Y plane either. I made a mental note to modify the object files to do something about this, so that off-square assembly is at least much more difficult. As is, tightening a nut can cause an axis to go off square. (Currently the X axis is less than 0.5mm off square to the right axis over the width of the frame, it may even be better, but that's about the limits of what I can guarantee for measure on that scale, particularly with the broken leg.)

Then comes the electronics...

Upload the test "blink" sketch to the Arduino. It works. Upload Marlin, success. Start Pronterface, connects to the arduino, test move the X axis, okay. Test move the Y axis, reversed direction from expected, but it works. Reverse Y direction in Marlin's config.h, re-upload, good. Move Z axis. Motors just shake... Re-adjust Z axis current on the RAMPS board, works for a bit then stops halfway to the homing point. Pronterface won't re-connect. Can't upload sketches to the arduino. At all. Buy replacement arduino. Note that even though original DID say arduino on the board, looks different from replacements purchased from Element 14/Newark. X/Y/Z axis all move well, and as expected. Bed heats up as desired, hot end, ditto. Extruder will not move, not even shake like X axis did. Double check current limits on the A4988, seems fine (similar to values for X and Y). Power everything down, connect extruder motor to the header for the X axis on the RAMPS board. Nothing. Move stuff back, and now the X axis doesn't move, either. Probable failed A4988. X axis motor works when connected to Y axis pin header, X axis pin header is okay if I swap the A4988 with the Y axis controller.

So, I've got more parts coming (Actually they may be here, since I got a pickup notice from the post office yesterday.)

It may be possible that I've got a bad RAMPS board, more likely I have a couple of failed A4988 controllers, but it was cheap and convenient to buy a set with the pololu controllers and a RAMPS 1.4 board, so that's what I did. I have not tested a known good controller on the extruder socket to see if it will move a different motor, but will do so. (I'm also expecting replacement stepper motors, since I know I have at least one that has failed.

Probably I should have made an enclosure that the electronics would actually fit in before attempting to run this thing, but I can't really see how the problems could have been caused by that, since I did make sure to have things on a non-conductive anti-static surface.

Electronic issues aside, are any of the other issues common with these kits? Missing screws, missed steps happening with shipped printed parts, parts with bad sizing, brittle or poor adhesion between layers?

Edited 1 time(s). Last edit at 12/16/2014 06:32PM by SupraGuy.

MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts
Re: Are all these kits this bad?
December 16, 2014 10:18PM
Most cheap kits have these issues due to plain carelessness/ignorance... I bought a Prusa i2 kit 2 years back and the seller didnt even know how the hot end actually works.. I ended up changing most of the parts in the kit.

Buy from reliable sources ..
Re: Are all these kits this bad?
December 17, 2014 12:10PM
When my buddy and I decided to build a 3D printer (Prusa i3) we didn't buy a kit as we wanted to be able to make sure we had quality components where it mattered - like the plastic parts, heat bed, j-head, motors, smooth rods etc Our cost was around CDN $650.00 (US $580). It did take a while to source parts from all over though.


My updated Instructable on our Prusa i3 Build
Re: Are all these kits this bad?
December 17, 2014 12:19PM
Well, pretty sure that the seller actually knows something about the workings... but is obviously more interested in getting stuff out the door to make money than in providing good quality parts, I suspect that the printed parts are basically made from the cheapest plastic that he can pump through his own 3D printer, and he's obviously not too concerned if there's a missed step in a part here and there.

Well, I did get parts last night,but was completely unable to test them because Windows.

My Windows 8 machine (Which I've pretty much determined is useless for anything else) has an interesting issue whereby as soon as the OS starts up, it is unable to recognize the keyboard and mouse. So... No logging in. All solutions that have been suggested to me assume that I've already logged in. Fan-freakin'-tastic. (For the record, I work with these things for a living, and I'm pretty good at my job.) Anyway the plan at this point is to get rid of the problem, which means... no more Windows 8. Currently deciding which linux distro to install so that I can actually get some reliability from the machine. Considering between Linux Mint MATE, Linux Mint Linux Mint Debian, and Kubuntu. So far the Mint Debian is a front-runner simply because updates are easier.

Anyway, I've got an extra set of stepper drivers, a second RAMPS board, and another arduino, which I'll probably connect to a Raspberry Pi to do some ADC conversion stuff for the carputer kit that I'm putting together. (Actually, the carputer is one of the big factors that I wanted the 3D printer for, so that I can integrate the Pi into the car in a cosmetically appropriate way.

MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts
Re: Are all these kits this bad?
December 17, 2014 01:49PM
I bought a i3 kit several weeks ago (Folger's). Some people here was delight with this kit. Well, I was a newbie into 3D printing and I did not choosed well. Kits are not equal. Mine is an acrylic kit, with v1.0 prussa PLA parts. Acrylic and PLA parts are rubbish. I had a lot of problems, the motors was the smallest possible (one is dead within 2 months), the hotend the cheapest possible (the heatsink broke), some parts were missing (zip ties, screws...) some in double. The brand new LM8UU bearings was china cheapest quality; loosing balls quickly, and they're far to be accurate. Combined with the 8mm rods (which are 7.8mm) the printing quality was poor... I had to change a lot of things to make it works properly : a motor, a new extruder, an E3D nozzle, a full set of Igus bearings (nice, smooth and quiet !), a new bed plate (the acrylic one used to bend when heated...), and I printed a lot of new parts to replaced the delaminating PLA ones. Most of the new printed parts was new versions (redesigned or from the i3 rework).

My advices : don't buy a cheap kit. There's reasons why some prusa kits cost $300 and others $600. Flee acrylic kits, and prefer aluminium or wood frames. Look the guide rails, some use Vgroove weels, and others 10mm rods and bearings, they are much more better than 8mm chinese ones. Look at the stepper motors torque, under 40N.cm (57oz.in) they are too small for the job, especialy for direct drive extruders. Buy ABS printed parts. PLA parts are too weak for mecanical parts IMHO. You want last evolution of the parts, not v1.0. Some people are sellers, some are makers. Buy a maker kit.

If I knew, I should have bought a Makerfarm's Prusa i3v for example.

Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)
Re: Are all these kits this bad?
December 17, 2014 09:50PM
Just a FYI you may already know the extruder will not move unless the hotend is above 180 degree, or whatever that safety setting is in your Marlin file.

Has caught be several times now, keep forgetting about it.
Re: Are all these kits this bad?
December 19, 2014 02:52PM
Yes, I am aware of that (Pronterface reports the serial output something like "dangerous extrude prevented")

I've taken steps to get around that. For the first few times by simply heating the hot end, and when that didn't work, I set up the min extrude temp to be 18 deg C... I've also tried plugging in the extruder motor to known working drivers, which is when the X stepper driver stopped driving the X axis, too. When THAT happened, I stopped testing the extruder motor.

I've been stalled on my troubleshooting for this because Windows 8 on my machine (which ONLY had Win8 because I was testing it as a platform for other software. When that failed miserably, I had no other real use for the machine, so I installed the software for the printer.) Tuesday, I got replacement parts for mine from an eBay vendor, and was going to test the X axis motor to see if it had been destroyed too, or if it was indeed the stepper driver destroyed from being connected to the extruder motor. I could not log in to the Windows 8 machine. It would not respond to the keyboard and mouse to allow a login. Not even the Caps Lock or Num Lock keys would respond via the LEDs, and an optical mouse gets no light at the sensor. Both keyboard and mouse work perfectly for BIOS settings, and even the repair console booting from CD. Nothing from somewhere after the Windows logo appears during boot and on. The Num lock light on the keyboard and mouse sensor light go out at the same time. tried everything that I know (I do tech support for a living, and I'm GOOD at it.) then looked online to see if it happens to anyone else. Found several hits, but all of the things that fixed it for other people, I'd already tried, with the exception of wiping the drive and starting over, or in the case of machines with the option, a factory restore. Actually called Microsoft support for the first time ever. All of the suggestions they had began with "At the logon screen do..." to which I would reply "I can't, the mouse and keyboard do not respond." their conclusion was that it must be a hardware issue despite the fact that everything works when NOT in Windows 8.

tl;dr: Windows 8 blows chunks.

Anyway, I've installed Linux on the machine, but I have to get the Arduino and Pronterface stuff installed on it yet. I haven't had a lot of time to work on it recently.
Re: Are all these kits this bad?
December 19, 2014 11:14PM
Yeah I have been down that road a few times as well, I have to laugh about the direction you went. I did similar thing, kept fighting an issue with an old laptop, that I though would work good for the the printer. Well the hard drive failed on me I priced a replacment IDE laptop hard drive, way too expensive. So I decided to give linux a try as well since I had a a really small IDE laptop size drive laying around not big enough for Windows. Well the graphics needed to render the 3D in linux did not work. I then found a Dell Laptop on Amazon on sale for 199.00 Win8, I didn't want that but Win7 was an extra 100.00 so I I figured worst case I could put Linux on it. So far that laptop with Win8 has been one of my best purchases; so no need to switch for me.

Well in the middle of all my issues, I spent the 10 dollars to buy an LCD and that let me do all the driver calibration that I needed.

I made it easier on myself and only used one motor for testing in the X position not installed in the printer and set up all the driver boards swapping them in, they may need to be adjusted a little later, but gets you in the ball park for all of them. Make sure you double check your wires are correct on the plugs. You can test them to figure it out. There are two pairs, each pair should test with low resistance. 1A,1B,2A,2B on the board, so when you plug them in you can reverse the direction of the motor by flipping the plug around.

Big tip do not use a metel screwdriver I burned up my Ramps and Arduino. The driver adjustment is metal and it grounds itself out, when you use a metal bladed screwdriver. I lucked out for awhile, but one time it just buzzed weird and bam the power cycIed and never worked again. So I ordered a ceramic screwdriver, but low budget way it use a wood BBQ stick, and sand it into a screwdriver, then use your lighter and harden the wood a little. I little trick I learned on some youtube show. lol.

Edited 1 time(s). Last edit at 12/19/2014 11:15PM by AquaticsLive.
Re: Are all these kits this bad?
December 20, 2014 05:07AM
Well, there was absolutely nothing wrong with my PC hardware. I installed 7 on it as well, just to test, and it runs that with excellent results. I installed Linux on a 120G solid state drive that I have as "extra" (I'm sure that I'll find a better use for the 2TB drive that was in there.)

Current status: I have my first 3D print now.

The extruder is a POS. I did something dumb... I trusted that since the extruder was sent to me assembled, and that it had a bit of filament in it, it MUST have been tested, at least rudimentary testing, right? BZZZZT! WRONG!

The roller bearing opposite the drive gear was absolutely locked in place, unable to move at all, putting WAY too much drag on the motor, so it couldn't spin in the slightest. A few minutes with a file solved that, but there is still a lot of drag on the filament going through the mechanism, before it gets near the tube to the hot end. I think I'm going to drill the entry area into the block a bit larger than necessary, since the drag seems to be coming from the roller/gear combination trying to curve the filament too much. I could see if the shape of the guides were to provide the pressure, but since there's a spring loaded roller in place, that SHOULDN'T be the case.

I have to do some callibration for sure.

Because of the amount of drag on the filament, it REALLY wants to air-print. If I provide a bit of force with my fingers, I can convince it to extrude on demand, though currently, I'm getting way too much filament extruded.

This was supposed to be a 20mm cube, but I aborted the print after about 5 layers. On the top photo you can see some evidence of air printing. On the bottom you can see that when the extruder is moving, ti's moving far too much. Maybe that's due to the pressure that I'm putting on with my fingers, but until I fix the extruder, it's hard to know.

the X/Y is supposed to be 20mm by 20mm. Though the drive gears for X and Y are identical, (So the actual drive should be as well) the "square" is actually a rectangle about 19.5mm by 17.5mm. For whatever reason, I do not know which is X and which is Y, since it looked square when I took it off, before I measured it. (My eyes are usually pretty good at picking up small distortions like that, but I still check before I trust it. Good thing. grinning smiley)

In the meantime, I'm kind of pumped that I'm this close, but it's nearly 3 AM, and I don't want to mess about with power tools when I've been up since 5 AM. I'm pretty sure that I need to drill to fix the extruder. Maybe I'll have better ideas tomorrow.

First project once this thing is running will be a spool holder. Using a broomstick zip-tied to the server rack over the printer for now. Next project might be something more fun.
Re: Are all these kits this bad?
December 20, 2014 09:15PM
Cool sounds like your getting it close. The entry side of the extruder, they must have not drilled it out after. I am not sure, but I have heard that your suppose to print the I3 parts hotter than normal with ABS to make the prints more solid, problem with that is it tends to make all the holes too small.

I would suggest taking the thing apart removing drive pulley and just making sure the filament slides through super smooth. After drilling it out use a lighter to warm it up and smooth out the edges helps too.

Then when you get it feeding nice, you will want to calibrate everything. There is a ton of places, but this one is I have saved, pretty easy. LINK
Re: Are all these kits this bad?
December 22, 2014 11:25AM
Well, after a rather sleep-deprived weekend, I got what I'd term my first successful print out of this thing (Though the scale is still off somewhat.) and now the Z axis is messing up again. Possibly just a heat issue, so I'll do some isolation testing. The Z axis motors always did make some unpleasant noises when homing, but were usually okay moving, but the last couple of tests, they got a bit odd. Like not coming back down the 5mm they go up between reaching bed temperature and reaching extruder temperature. (Pause the print when it starts the skirt, home the Z axis and resume.)

I haven't tried printing anything with ABS yet, and I think that I'm now underfeeding the filament a bit. I tried making a tsuba for a bokken, but the scale is off, so the opening was too small. Well, I'll make another when I re-calibrate. the print head seems to be working well, now that I've drilled it out, smoothed it and basically rebuilt it.
Re: Are all these kits this bad?
December 22, 2014 11:56AM
Good Luck, little more tweaking left. Well that never ends lol, I am always tinkering.
Re: Are all these kits this bad?
December 30, 2014 07:22AM
If you want to move the extruder without heating the hotend or fudging the minimum extrusion temperature in the firmware, just send the printer M302 and it will allow the extruder to move while hotend is cold.

Please add your printer design to [reprap.org]
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