some symptoms and no ideas how to solve them

Hi,
i tried to print the nozzle mount for cap screws. But i got a non 90 degree mount, which lowered the fan mount even more...

first image:
[www.dropbox.com]

the left one is printed without axis compensation and the right one with it. for myself i do not see much difference. what i find odd is that the right upper edge stretches upward.

second image:
[www.dropbox.com]

this pic shows how worse the YZ-combination is. the problem is, the z-extrusion is 90 degrees to the y-extrusion. one thing that could is that it isn't 90 degrees anymore, because i have to carry my ormerod to a table to print with it.

third image:
[www.dropbox.com]

here is the problem that the right upper corner gets worse with every layer.


also i have the problem that my prints are starting to warp. i print pla. every time i try to print the testpiece, it starts to warp where x y and z meets. this corner is pointing to X0 Y0. like this [reprappro.com]

i hope someone can help me

kind regards
david

Edited 2 time(s). Last edit at 06/06/2014 04:19PM by x4FF3.

Hi x4FF3, welcome to the forum!

I have set the Z axis accurately perpendicular to the Y axis. I have also replaced the MDF bed support by an aluminium one (these are now available from Davek, see [forums.reprap.org]) with three bed-levelling screws. This is a modification that I highly recommend. So my axes are perpendicular, and I don't use axis compensation at all. Maybe I would need it if I were printing something very tall.

There is a lot of backwash from the fan in the original design, and this can cause warping of large PLA prints. A fan inlet duct suppresses the backwash. You can find the one I use here [github.com]. You will need long countersink screws to fit it. There are several other fan inlet duct designs on this forum, including the original one by kwikius that mine is based on.

Check that your y-axis belt is not slipping. Usually it causes stepped prints when it slips, but perhaps in your case it is causing the slope on your prints. The quick solution is to use a cable time as described on the RRP troubleshooting page. The better solution is to print Matt's y-belt fasteners, and my spacers to allow you to adjust the y-belt tension. See the link I gave earlier for these.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

i forgot to mention i already have the aluminium bed from davek and bed-levelling screws with springs. also i have an endswitch for my z-axis, so i don't need the ir-probe. the y-axis belt is already ziptied and is tight, maybe to tight.
so i will print the y-belt fasteners and the fan inlet.

thanks for those great tips dc42!

kind regards
david

Hi David, DC42 (another David), has just about covered everything.
I run a level bed here, as alot of us do. It's easier to do if you can get hold of a piece of 3mm Ally plate the same size, or a fraction bigger that the MDF Bed.
Just use the MDF Bed as a template for the three Big Square holes, and I cheated, by retaining the MDF for it's alignment holes, and placed the Ally Bed on top of it.
Then you can run a level Bed your self.
The main problem I think you have is that your Z-axis isn't quite at 90'. I discovered mine had slipped slightly when I printed some gears, and they were terrable.
The set square they send out with the kits is ok, but a bit tricky to use. If you can use a propper set sqquare it's alot eaier to check and setup. It only needs to be a fraction out.
My printer gets lifted by the Z axis, so has a tendancy to slip sometimes. (There's not really a convienient lifting point to put it in and out of it's carrying case).
And I've found you can just push the Z-axis upright, quite easily without messing around slackening the screws.
Also as DC said above, check your Y Belt tention. It's difficult to discribe, but basicaly, When the Table is moving look at where the Belt leaves the stepper motor pulley.
If when the Table is moving to a lower Y position it's humping up, then it's to Slack. But you don't want it to be to tight either. i.e. Don't get a note from it when you pluck it.
It's a difficult thing to explain... When it's to tight, the motor struggles to move the table.

On my printer I don't use the compensation so can't help with the settings.

As for the Warping, as DC says, a better Fan/Duct helps, but for a small item like the Nozzle Mount, use a 10mm Brim, with a Bed temp of 57' and a HotEnd of 195'.
Below you will see a couple of Nozzle Mounts listed, one with a 1mm extra added to it to raise the probe height.

When you do get to the bottom of it, and fix it, you might also find the 9mm Bearing sleeve useful, so you can swap the 9mm on the X-carriage, for the 10mm used as the Y-idler.
Hope you find the problem soon.
Regards,
Kim..

---

Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

Hi Kim, dc42,

as suggested i tried to print a part with a brim. but it does not stick properly.

video: [www.dropbox.com]

the head moves to fast in my opinion. my first layer speed is at 15mm/s. but the brim is printed faster. which option in slic3r would change this speed?

kind regards
david

This seems like an odd suggestion, but it's something I found - ensure that your glass is held firmly in place, because the friction when the hotend moves dragging plastic can be enough to move the glass slightly, causing strange layer shifts that can be difficult to identify because they are not always constant.

Hi David, in your video your Nozzle/Heater Block Assembly is at an angle....
Slacken off the two screws in the Nozzle Mount, and while tightening them up again, pinch in the Fan Duct towards the X-axis arm.
I think that is the main problem there. Your Nozzle is at such a crazy angle that one side of the nozzle is at the correct height, but the other side of it is way out.
It really needs to be as level as you can get it. If doing that, doeesn't level it up, then add a small sliver of wood or paper under one side of the screws to get it
to level up. Once it's level I think your problems will be over....
As for the Speed it comes under Modifiers, First Layer Speed... It's a percentage.... Try 45%

---

Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

PS If you look at the top face of the Heater Block, that is the angle your Nozzle is at.... And it looks like 5-10' out to me at a guess.

---

Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

Hi Kim,

so i changed the bearing which runs along the x-axis arm from a 9mm to 10mm and added washers to the screws. the angle got better imho, but it still "eats" the brim.

video: [www.dropbox.com]

then i made a spacer for my filament holder in openSCAD and printed it.

pic: [www.dropbox.com]

i printed it without brim, came out quite nice. at the moment i try to print the nozzle mount for cap screws again, to check if the angle is not as bad as last time.

kind regards
david

Hi David, yes it does look abit better. It's still leaning back a fraction, so I'd use abit of folded up paper along one edge ot the ally block to level it, and raise the height of the nozzle by 0.1 - 0.2 and try that.
How tight are your Belts, as they are quite tricky to get right. Make sure when it's printing that the belt isn't humping up on the slack side of motor pulley when it prints.
And the belt mustn't be that tight either... There's not a good way to discribe it unfortunately.
It looked to be picking up the brim as it was doing a -Y move, so I'd check your X axis belt first. Your so nearly at the point of printing well.

If you look at the underside (table side) of the spacer print, you'll see the filament lines. If they aren't uniform in both directions then your nozzle still needs to be leveled abit.
It tends to push the plastic on to the glass in one direction (so fatter), and in the other allows the plastic to roll off the nozzle, so is thinner, and there's normal a thin gap to one side also.
The Nozzle needs to be as level as you can get in both directions.
Also, In Slic3r, theres a setting for the First Layer of 200% Filament.. Try decreasing that to 150%.
The Brim it was printing was abit FLAT, and chubby, which means the nozzle was to close to the glass. As I said above try setting it a fraction higher, just 0.1 or there abouts, and I think your problems will be over.
Also look at the Spacers Roundness.... DC42s firmware does circle really well, and if it's not perfectly round, that points to the Belts not being tensioned correctly.

Also, when we're starting out, there's a tendancy to use to much Heat... Not that this is a problem in your case I think, but try to stick to 57' for the table, and 195' for the HotEnd, with only 5-10' of change for a particular filament.
Table heat it quite important, as the Plastic won't stick properly to a cold table, but if you get it to hot (60' for PLA) then it starts to Blister.

Your so close to getting perfect prints there. Don't get disheartend, as it's a steep learning curve to start with....
Hope all that helps....
It is tricky to get started...
All the Best,
Kim..

---

Please send me a PM if you have suggestions, or problems with Big Blue 360.
I won't see comments in threads, as I move around to much.
Working Link to Big Blue 360 Complete

The plastic is not sticking to the bed well enough. possible causes are - (1) bed is not clean enough (grease or soap residue etc). (2) bed is not hot enough. (3) Nozzle is too high.

The first layer of plastic needs to be "squished" onto the bed, and so better adhesion is obtained if the nozzle is slightly closer than the layer height - which means having the zero set point slightly lower than the bed. Try setting the Z zero as you usually do, but then lower the Z height by 0.05mm and setting that as the zero point.

e.g.

G1 Z-.05
G92 Z0


Dave
(#106)

Hi,

so some things could be sorted out and some not i tightened the belts via this method [www.youtube.com]
so at first i put the temperature of the heated bed to 67C, prints are sticking much better now . also after tightening the belt, the printer got more silent. which i think is a good sign. the bad thing about this, is that circles are not really circles anymore. on the y-axis is the radius slightly smaller. i tried to ramp up the mA of the y-motor to 820, which did not help. (shall i go to 850?).

the other major problem is cooling. i printed the x-axis fan holder [www.thingiverse.com]. since i use a 40mm fan with it, the backside of my prints got better. still the frontside has often alot of filament strings. like in this picture: [www.dropbox.com] and even little overhangs look messy: [www.dropbox.com] i print first layer at 200C and the other layers at 190C.

what i noticed that the fan speed gets significantly lower, when the bed starts to heat. at the moment i use a different 40mm fan at the hotend, because i broke the fan which came in the kit. it is a little bit slower. it's this one: [de.farnell.com] and i use iamburny's one-piece-hotend-duct.
would it help when i use a PSU with more amps to get rid of fans getting slower when the bed heats up? like this one: [www.ebay.de]

Try 1000mA for the Y motor current, first layer temperature 195C, other layers 185C or 180C.

I don't think the slight slowdown of the fan when the bed heater is on is very significant, but if you want a better ATX PSU, I can recommend the Corsair CX430M. If you search this forum for that model number, you should find the thread in which I reported how much better it was than the Alpine PSU that came with the kit. However, a PSU such as this one [www.ebay.co.uk] (I have the the 300W version) is even better, although it required some mains voltage wiring and a safety cover (which you can print).

Edited 3 time(s). Last edit at 06/24/2014 07:18PM by dc42.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

so long time no post

update on my changes:

changed the current for X, Z and E to 1000 and for Y to 1100 with cooling. also i bought an EVGA ATX PSU (little cheaper then the Corsair, same 12V 34A). makes heating the bed a pleasure, much faster now! also tried different printing temperatures for my PLA. settled with 190 now. because with 185 i had extrusion problems.

but still i have problems with warping. i cannot print anything with a little overhang. i tried to print this earbud holder: [www.thingiverse.com] but as the printer got to the upper part, the warping killed the print... [www.dropbox.com]

i have the deflector installed on the fan. so backwash is reduced. i played a little with slic3r settings and increased the retraction, which did help a little.

so in conclusion, can someone recommend a PLA supplier?

One other thing is to ensure that there are no draughts while printing - just a single draught of air across the bed can cause a corner of the print to lift after which the whole side of the print begins warping.

Dave
(#106)