SoliForum - 3D Printing Community — Bearings Don't Fit ABS Printed Parts

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (brucesdad13) — Wed, 02 Nov 2016 17:33:23 +0000

Ok. Thanks!

heartless wrote:

yeah, that is definitely Z wobble.
a bed stabilizer in the front will help, but not eliminate it.
you may want to look into a adding a "slop nut" on the Z rod... there are several options out there already - take a look through the "Hacks and Mods" section

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (heartless) — Wed, 02 Nov 2016 11:52:15 +0000

yeah, that is definitely Z wobble.

a bed stabilizer in the front will help, but not eliminate it.

you may want to look into a adding a "slop nut" on the Z rod... there are several options out there already - take a look through the "Hacks and Mods" section

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (brucesdad13) — Wed, 02 Nov 2016 02:25:05 +0000

Here's an example after mucking with electronics. I think I need to recalibrate steps for all motors after tuning vref? Moire is mostly gone but z wobble visible at corners if I'm interpreting correctly ...

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (brucesdad13) — Wed, 02 Nov 2016 01:42:01 +0000

Sorry for the nonphoto--was at work. What I'm seeing resembles the Moire. In the beginning a few weeks ago I had really really bad Z wobble. This evening I replaced the 20k ohm resistor on the Pololu 4988 stepper with a salvaged 51k ohm per RepRap wiki. I then used a multimeter to set correct Vref. Seems like Y was a ways off from what it should have been at. I didn't have the wherewithall to salvage more resistors but wonder if it's worth it to get more accurate Vref set on the XYZ? Haven't replaced a surface mount resistor in many years. My eyes are definitely aging. These things are so TINY!

heartless wrote:

just to clarify (since you didnt share a picture of what you are seeing)

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (heartless) — Tue, 01 Nov 2016 22:40:32 +0000

just to clarify (since you didnt share a picture of what you are seeing)

this is moire:

and this is Z wobble (image grabbed from online):

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (brucesdad13) — Tue, 01 Nov 2016 17:52:26 +0000

Cool ordered one

wardjr wrote:

Learning is the fun part, an easy solution that your problem is to put a DRV8825 on the E:
https://www.printitindustries.com/colle … er-drivers
This will allow 1/32 stepping and is easier to adjust out the Moiré.
There is no question that the teeth on the stock drive gear are less than desirable. But, unless you are seeing filament dust it is probably doing its job just fine.

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (wardjr) — Tue, 01 Nov 2016 17:31:29 +0000

Learning is the fun part, an easy solution that your problem is to put a DRV8825 on the E:
https://www.printitindustries.com/colle … er-drivers
This will allow 1/32 stepping and is easier to adjust out the Moiré.
There is no question that the teeth on the stock drive gear are less than desirable. But, unless you are seeing filament dust it is probably doing its job just fine.

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (brucesdad13) — Tue, 01 Nov 2016 15:49:40 +0000

Ahh... Thanks! I'll take a look at a geared extruder. My extruder motor has a hobbed bolt of some kind that presses against a roller bearing. Maybe it's just not sharp enough? In a few days I should have the parts to do a cheap m3 rod Z axis. I'm thinking I need to stiffen the SD2 frame somewhat... it's coming along. More of a project than I expected but enjoying the learning and will apply it to larger machine. I found a page on replacing the resistors on the Pololu stepper driver that allows easier tuning. I haven't yet looked at the motors... http://reprap.org/wiki/Pololu_stepper_driver_board

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (wardjr) — Tue, 01 Nov 2016 14:28:38 +0000

That pattern is called moire and is caused by the pulse of the extruder motor. You can adjust VREF to reduce it. A geared extruder would eliminate it. As would a 1/32 driver or a .9 motor. Seems as though lately one of the favorite choices has been to install a Hobb Goblin to help reduce Moiré https://www.printitindustries.com/produ … bb-goblin.

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (brucesdad13) — Tue, 01 Nov 2016 13:56:59 +0000

Well... I replaced my ATMega644p with an ATMega1284p last night. It came with OptiBoot bootloader and that took some time to get my head around. Anyways, back up and running with some room to grow and play with whatever code mods might be helpful. I then tried to print some tests with ABS (bed slurried, leveled, 105C, enclosure on, some insulation on the enclosure) and parts were still warping and coming loose and getting dragged. PLA prints so easily ;'(

Help! BTW I ordered a digital caliper... I noticed when I tried just a few layers of my test cube that I am underextruding. It seemed like I was spot on if I measured too many layers. There's a visible pattern on the walls/perimeter that stays from one test cube to the next... is that the threads on the Z axis?

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (carl_m1968) — Tue, 01 Nov 2016 01:39:41 +0000

I make it a rule of thumb that structural and functional parts are always printed with 80 to 100 percent infill.

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (brucesdad13) — Tue, 01 Nov 2016 00:59:22 +0000

Ok. I'll give it a shot reprinting them at a higher infill so they don't eventually break. They are made of ABS and after a few days of printing no visible signs of wear.

AZERATE wrote:

+1 to printing hardware!
Calibrating your machine is crucial for the inevitable day you need to print your own hardware or replacement parts.
OP- as a side note, it seems you printed your carriages with a low infill. It is highly recommended you print them with no less than 80% infill, but 100% is best.

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (brucesdad13) — Tue, 01 Nov 2016 00:57:40 +0000

I have the wooden bed so that Thing won't fit easily... maybe I could screw it on?

heartless wrote:

I am no expert by any means, but it seems to me that the springs - while allowing full Z movement - might not stop the shaking of the bed. Yes, it may limit/reduce it a bit, but I dont think it would stop it completely. The only way to do that is to have a rigid stabilizer.
I used this one: http://www.thingiverse.com/thing:195266 with some brass tubing I had on hand. it works very well at stopping the front of the bed wiggle... the only problem is loosing a little Z height

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (heartless) — Mon, 31 Oct 2016 11:53:39 +0000

I am no expert by any means, but it seems to me that the springs - while allowing full Z movement - might not stop the shaking of the bed. Yes, it may limit/reduce it a bit, but I dont think it would stop it completely. The only way to do that is to have a rigid stabilizer.

I used this one: http://www.thingiverse.com/thing:195266 with some brass tubing I had on hand. it works very well at stopping the front of the bed wiggle... the only problem is loosing a little Z height

Re: Bearings Don't Fit ABS Printed Parts

null@example.com (brucesdad13) — Mon, 31 Oct 2016 02:40:38 +0000

I've been doing much better thanks to all of your advice and switching to PLA for the time being. Here are a few prints from over the weekend. I broke the glass trying to remove this print from blue painters tape covered bed. Thankfully I had extra glass but wondering if maybe I need a thinner tool? ABS always just popped right off of the clean glass.

Still a tiny bit of warping at the corners with PLA but nothing like ABS. I am curious about the bed shifting left right (X-axis). I have seen some people used this... do you recommend: http://tomhorsley.com/hardware/solidood … table.html ??

I am using this spring setup and it seems to work to remove backlash on Z screw http://www.thingiverse.com/thing:1273137