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How far is TOO FAR

Posted by wmhosea 
How far is TOO FAR
December 11, 2017 04:08PM
Hello Fellow RepRappers!

I have just finished building my second Reprap (Lets just say it was a snap to build! LOL) and I thought I would turn my attention back to my first 3d Printer. Its a CheapO printer kit made by Mistake.

Actually, it is a Linear Delta by Anycubic and it really was a mistake. To date I have been unsuccessful in printing anything larger than a small gear (about the size of a half-dollar) and I am considering some "upgrades". My problem is every time I start to make plans, I get closer to a new machine than I do to an upgrade of what I already have. I would love to hear from the community on what you would do in this situation. BUT FIRST, here are some of the issues I have to contend with.

1. The "Y" Axis stops moving entirely after about 10 minutes and I can only guess why.
There is little to no airflow where the control board is so I tend to believe that the stepper driver is overheating. Why then is it just the Y axis that is affected? I have swapped drivers around but it's always the Y axis that stops moving!?!?

2. The printer is kind of a jerk. Seriously, it's not smooth at all. From the start It will go for 2-5 seconds then stop for a moment, then go and stop, and go go go and stop. It doesn't make any difference if I am connected via USB or if I save the job on the local SD card.
I have read that Delta printers require a bit more than an 8 bit processor. The control board that came with the kit is a "Trigorilla" which they don't even make anymore and I wouldn't buy in the first place anyway. After reading on all the popular types of boards I almost want to get a DuetWifi. Aside from going all out and getting what appears to be the creme of the crop, what other boards have you had success with in a Delta?

3. The Hotend drools, a lot.
When I first start a print and it is heating up, I will get a mess of plastic out on the print bed before the printing even starts. By the time the effector starts moving there is nothing coming out of the hotend for almost 30 seconds. I have played with the temperature a bit but the results are always similar. The cold end appears to still be extruding so I don't think that is the issue. I was thinking of getting a E3d v6 Full or Lite. Thoughts?

4. Bed leveling is controlled by some screws on top of the carriages. The screws hit the limit switches during the homing process so leveling is supposedly achieved by adjusting the screws.
I find this method to be very unreliable. Using a probe seems much more better, but I have no experience with them. Any thoughts from Delta owners on this?


So my plan is to

Replace the board with a DuetWifi
While I am at it, I will Replace the motors with .9° motors to take full advantage of the 256 micro stepping
Replace the hotend with an E3D V6
Replace the extruder just to be sure of quality
Replace the Effector with a Smart Effector also from Duet3D
Replace the glass bed with an aluminum heat bed so I can use ABS


And then... I will have a brand new machine for only 3 times the price I originally paid for it. Or, I can just get a new control board, add some air flow and go from there. But if I do that I might as well get a new hot end; and if I do that then it wouldn't be much more to get the new.....


So how far would you go?



Discuss
Re: How far is TOO FAR
December 11, 2017 05:44PM
IMO the important question is: how good are the printer mechanics? If the mechanics are accurate, then an upgrade to Duet WiFi electronics will be a good investment. But if the mechanics are poor, then much as I would like you to buy the board that I co-designed and support, I would have to concede that it might be better to spend the money on better mechanics first.

I suggest you postpone the upgrade to 0.9deg motors. Unless you have missed microsteps caused by the stepper drivers (in which case you need to change to electronics with better stepper drivers), changing to 0.9deg motors gives only a small improvement in print quality. Also if you want high travel speeds, then along with 0.9deg motors you need 24V power. So I suggest you wait until you have good prints with the existing motors before you upgrade them. You will find print quality comparisons in one of my blog entries on upgrading my original large Kossel build.

Regarding the hot end, in my experience hot ends lined with PTFE are much more forgiving then all-metal hot ends, in particular they are much more tolerant of high retractions, which help prevent filament oozing. Therefore, unless you want to print filaments that need high temperatures, I suggest the E3D Lite 6.

HTH David

Edited 2 time(s). Last edit at 12/12/2017 04:52AM by dc42.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: How far is TOO FAR
December 11, 2017 10:24PM
If you suspect that cooling is an issue, duct-tape a 5015 blower fan in place pointing at the suspect driver, and see if that cures it. If it does, work out a long-term fix. If it doesn't, look for what is wrong.

If the motor stops entirely, my guess is that you have a dry joint or similar on the board. If it was the driver itself overheating, it would be more intermittent.

Don't know about the jerkiness; I have a Delta running on an 8-bit board, and I don't see anything like you describe. What software are you running?

Drooling is a difficult problem with Deltas. There's a lot of slack in the Bowden tube and connectors between the hot-end and extruder. You could try increasing your retraction setting... it should be in the region 5mm or so.

I think (@DC42 knows a lot more) that probe-based bed-leveling depends on the assumption that the geometry is right; the towers must all be at right angles to the bed (i.e. vertical towers and horizontal bed), the towers are evenly spaced, the diagonal arms are parallel, etc. If you don't have the right geometry, no amount of bed-leveling will fix it. The screws and limit switches allow you to set the home position where all the carriages are the same number of steps above the bed. I've found that this works well for me (after I spent some time ensuring the geometry was right).
Re: How far is TOO FAR
December 12, 2017 01:56PM
Hotends aren't that expensive, and it definitely sounds like you need one.

Sounds like there are some serious control issues. Your Y axis stepper driver isn't happy, it's either overheating, or is underdriven and your motor isn't responding once IT heats up. the pauses would make me crazy.

There are several control electronics sets, hotends, and the like available on Amazon for reasonably cheap, if "that's all" that's wrong with it.

Me? I'll qualify this by saying that this thing is a hobby. I have an I3 that frankly sucks. It wasn't too bad at first, but it hasn't improved with age, and about a year and a half ago, I threw it in the closet in disgust when it could no longer manage to track a circle. Recently I pulled it out, and I'm working on it again to see if I can make it accurate again. Ultimately the economical solution to fixing it was to buy another printer.

Now if what I wanted was just a working printer, I'd be done right there. Salvage the old one for parts, and forget about it. no use in throwing good money after bad. I'm not done. I want to use the parts of the old kit that don't suck to see if I can make something that's more accurate, even if it's a bit slower. (The new printer -- Assembly to be finished tonight, if all goes well -- should be fast enough for daily use.) if I succeed, great, but I'm taking the risk that I might end up spending the money and still having junk. i know that I'm taking that risk, and I'm okay with that.


MBot3D Printer
MakerBot clone Kit from Amazon
Added heated bed.

Leadscrew self-built printer (in progress)
Duet Wifi, Precision Piezo parts
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