Tag Archives: Prototyping

3D Printing: Ashtar K Printer: Electronics

by Rene K. Mueller · published November 25, 2018 Technology 3D Printing, Ashtar K 3D Printer, CTC DIY i3 Pro B, Prototyping, Prusa i3, RAMPS 1.4

Updates:

2018/12/05: added MKS Gen L as alternative, for Ashtar C #1
2018/11/25: added RAMPS 1.4 as alternative, for Ashtar K #2
2018/08/28: initial version with CTC DIY I3 Kit

Sourcing Parts

The past months (2018/08) I began to use Aliexpress for ordering electronics – even prior going into 3d printing – and the past weeks my development cycles pretty much were depending on the 20-25 days delay until items arrived from China to Switzerland – and one develops some skill to anticipate what one would require as next – but some things only become known once you really tested parts thoroughly.

Anyway, the CTC DIY I3 Pro B (Geeetech DIY I3 Pro B clone) was still sold via Ebay (2018/08), at a price as low as EUR 80 incl. shipment, which is a true bargain.

Aliexpress (2018/08):

MKS Gen L mainboard (incl. drivers) with LCD (with dialer), 200×200 heatbed, end stops, cables: EUR 50
PSU 12V 240W: EUR 20
5x Nema 17 45Nm stepper motors: EUR 35
Total: EUR 105 (without endstops and various cables to connect all together)

CTC DIY I3 Pro B Kit (2018/08):

Anet 1.0 mainboard, with 2 Lines LCD (4 buttons), 200×200 heatbed, end stop, cables, PSU 12V 240W, 5x Nema 17 45Nm stepper motors
Total EUR 80 (all cables included)

So I decided to get another CTC DIY to source the parts in one go, and likely upgrade later with individually sourced parts to have dual extruder motors (two color or material printing).

In 2018/11, when I started to build a second Ashtar K 38x30x33 #2 I checked Ebay with following prices:

Ebay (2018/11):

MKS Gen L: EUR 28
- MKS Gen L mainboard: EUR 16
- 5x A4988 drivers: EUR 6
- RepRap Full Graphic LCD: EUR 11
RAMPS 1.4 with Arduino Mega, 5x A4988 drivers, Full Graphic LCD: EUR 28
5x Nema 17 40-50Nm stepper motors with cables: EUR 26-35
PSU 12V 240W: EUR 20
Total EUR 74 – 83 (missing: endstops and various cables to connect all)

Burning Bootloader on Anet 1.0 Board

For now I use an “Anet V1.0” controller board (Atmel 1284P), as part of a “CTC DIY Kit” as mentioned, and it required some preparation:

using Arduino Uno R3 (clone) and upload “Arduino ISP”
attach Anet V1.0 board (detach all other cables) to Uno R3
run “Burning Bootloader” with “Arduino as ISP” as writer
downloading Marlin and edit main Configuration.h (not yet published) to match my specifications
upload new firmware Marlin to “Anet V1.0” via USB upload

RAMPS 1.4 with RepRap Discount Full Graphic LCD

RAMPS 1.4 Schematic + Pinout For the 2nd Ashtar K 3D Printer I used (2018/11) RAMPS 1.4 combo with Arduino Mega, which was easy to upload new firmware. RAMPS 1.4 is Open Hardware, the entire schematic and pinout is available or download diagram with pinout as one image (same as on the side) – but it’s also a hassle to plug correctly as the board plug descriptions are tiny or covered by parts so one has to consult documentation in details, and there many ways to do wrong (reverse or misalign plugs) and most of these can and do damage either the RAMPS 1.4 shield and/or the Arduino Mega beneath, including misaligning the endstops.

Endstops

using C and NC on the endstop and the board (power connector on the left) above the 2x Z motor connectors: XMIN, XMAX, YMIN, XMAX, ZMIN, XMAX, each:
- top (Signal) -> C
- middle (Ground) -> NC
- bottom (5V) -> empty

while waiting for proper endstops to arrive, I salvaged microswitches from a faulty computer mouse to work as endstops

Marlin Firmware Changes

Configuration.h:
- #define MOTHERBOARD BOARD_RAMPS_14_EFB
- #define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
Configuration_adv.h:
- commented out #define MENU_HOLLOW_FRAME so selected item is inversed
pin_RAMPS.h:
- see #if ENABLED(REPRAP_DISCOUNT_SMART_CONTROLLER) and the following #if ENABLED(CR10_STOCKDISPLAY) after the #else check BTN_EN1 and BTN_EN2 and reverse the pins (31 <-> 33) so clockwise dialing goes down (and not up).

MKS Gen L

20181205_135417

Configuration.h:
- #define MOTHERBOARD BOARD_MKS_GEN_L

As far I can tell the end-stops take DuPont females and pin order is the same as with RAMPS 1.4, but orientation is crucial – otherwise the GND and VCC is shorted.

The plan is to use this board for Ashtar C #1.

I update this post as I go along.

3D Printing: Ashtar K Printer: Printing #2

by Rene K. Mueller · published September 30, 2018 Technology 2020, 3D Printing, Ashtar K, Prototyping, Prusa i3, RepRap

Upgrading X Motor Mount

Printing new X motor mount on CTC DIY I3, and replacing it on the new Ashtar K: CTC DIY I3 prints quite reliably – there is nothing to clean up – the piece I attach it right away:

Ashtar K lacked a proper print surface (before I received the black sticker surface), otherwise I would have printed the piece on itself.

Black Sticker as Bed Surface

The 400×400 black sticker arrived, and I cut it into 400x300mm and put it on the mirror – which worked well, and so far I can tell the surface is very very flat, much better than on alu heat bed.

bed-corner-detail Current bed setup (top to bottom):

400x300mm black sticker (“frosted sticker”), apprx. 0.6mm thick
400x300mm 3mm thick mirror
210x210mm 12V alu heat bed
various cork patches under heat bed
10mm light black foam material
420x320mm 6mm plywood (white painted) as Y carriage
- 4x printed corner mounts holding 3.7mm thick sticker/mirror combo
- M3 x 35
- M3 washer (below printed corner mount)
- Spring (20mm long, ~10mm OD, 1mm wire)
- M3 washer
- printed knob (below plywood), 30mm OD, 8mm thick, M3 nut inserted

Now that I have a good print surface I finally printed pieces for itself.

Mounting the 400×300 bed (OSB 6mm, white painted) with 200×200 heat bed (which I hardly use, as I started to print on cold bed):

I currently use the white PU steel enhanced GT2 belts, and it produces hard edges, some ghosting, but more precise prints than the black rubber GT2 belts which just stretch too much – I have to research this more closely – about the type of reinforcement and the use with more heavy beds (Y carriage).

Just for the record regarding Y carriage (2018/09):

420×320 carriage:

4mm plywood flexes, but has been quite flat – not recommended
6mm plywood hardly flexes, but has been hard to buy truly flat – and so far my attempt to flatten it did not work well – not recommend unless it’s flat
6mm OSB quite flat, does not flex much (3 or 4 sliders) – recommended

320×320 carriage (for 300×300 bed):

4mm plywood works (3 sliders, 4 sliders recommended)
6mm plywood works (3 sliders, 4 sliders possible if plywood is truly flat <0.2mm difference)
6mm OSB quite flat, doesn’t flex (not yet tested)

Just to explain my thought or decision process for my setup:

the mirror should not be bend (of course)
the support structure should not be the edge mounts, but the foam in between
the carriage can be bent, but not flex
revelation: already bent means the springs with screws might extend the bent further with a flexing carriage, and not counter act – as the mirror should stay flat

so, even though the springs/screws and edge mount can adjust, the carriage should be fairly flat, and not flex at all – this way the edge mounts holding the glass/mirror only stabilize position. Main force to hold the glass/mirror, for my setup, is the foam in between. So, there is no “spring” induced vibration back/forth introduced, but the foam neutralizes such vibrations – and hardly adds weight/inertia.

Sliders & Belt Mount Positions

Top view with see-through (best mark “0,0” on both sides to keep reference).

bed-layouts

400×300 vs 300×300 Bed

Originally I focused on 300×300 bed at least, with some tweaking and narrow X carriage I was able to reach 380×300 printable bed, so it was suitable to use 400×300 plate as well.

It takes me about 5min to mount new bed, downgrade from 400×300 to 300×300:

Changes needed:

move Y endstop switch from left to Y carriage extrusion to the right side
Y stopper mounted on the bed needs to placed accordingly

With 300×300 bed the 0,0 is now plenty outside of the bed, with 400×300 the 0,0 is near the printed bed mount.

Setting Offsets for 300×300 bed

With 300×300 bed the 0,0 is now +32mm to right and +25mm deeper, hence the Gcode M206 is set like this:

M206 X-32 Y-25

H Plate/Module as X Carriage

The 3 wheels module riding on the 2020 alu extrusion I named “V plate” due the shape, the 4 wheels module “H plate” providing more stability or rigidity for use as X axis carriage, when the nozzle runs over slightly unclean extrusion and tilts upside. For the X carriage I choose a narrow (48mm wide hole-to-hole) version:

: Belt mount and hotend holder using same mounting holes

It’s the first/early version, the adjustment screws (M3x10) are very or too close to the bed for my taste, next version will use M3x8 and give more spacing. I like to keep the hotend close to the X carriage so not to waste Z space.

Additionally I made a new hotend mount so it would use another mounting holes than belt mount:

: Belt mount and hotend holder using same mounting holes

: Belt mount and hotend holder separate

But now it’s harder to reach the hotend mount holes due the part cooler – oh well.

After few days, I noticed one wheel stopped to turn, no longer touching the alu extrusion – I guess the carriage slowly balanced itself and triangulized, no longer use the 4th wheel. I re-tighten the 4th wheel gently so it would roll again.

Z Couplers: To Wobble or Not To Wobble

As I posted before, I suspect the Z couplers to be the main source for Z wobbles, as the threaded rods may look and are cheap but they are mostly straight – the wobble actually is caused, after close observation, from the misalignment which happens when you screw the metal couplers on, in particular if you attached the lead screw or threaded rod with uneven surface – the thightening screws may or may not attach cleanly – and thereby push the Z rods out of the center of the Z stepper motor – when the Z thread holding the X axis is fixed, the resulting wobble is worse at low Z heights; and if you fasten the Z rods at the top, the wobble gets even worse.

couple-excentric

A simple remedy I found is to use printed couplers, two pieces which are screwed together with 4x M3 screws and nuts, a bit of an overkill, and a bit time consuming to fasten: incrementally tighten each screw over and over until all are tight – but I think it’s worth it: the two halves attach evenly and the PLA or ABS or whatever you printed the couplers, is soft enough so the threads of the Z rods carve themselves evenly into the coupler, and self center themselves this way – result is better centric attachment of the Z rods, not perfect but acceptable and better than poorly manufactured metal couplers.

couple-excentric2

: Alu 5mm to 6mm coupler

: PLA printed 5mm to 6mm coupler

As mentioned before, I switched from M8 to M6 for the Z axis the M6 provides 1mm movement per full turn, and is more flexible to even out out-of-center wobbles, better than the stiffer M8 threaded rod. If using couplers at all, and likely introduce out-of-center mounting, rather use a more flexible lead-screw or threaded rod than a stiffer one.

3D Printing: Ashtar K Printer: Printing #1

by Rene K. Mueller · published September 4, 2018 Technology 2020, 2020 Alu Extrusion, 3D Printing, Ashtar K, Prototyping, Prusa i3, RepRap, Slider Carriage, Sliders, V Carriages, Wheel Carriage

It has been a few days (2018/09/04), since Ashtar K happen to be able to print, the heat bed still unfinished, some prints illustrated below are done with no leveling screws, the mirror just taped on the Y carriage – don’t laugh – later prints I had proper carriage and leveling screws included; a proper build surface I still wait for in the mail (400×400 black sticker to be cut in shape) – anyway, here some of the early prints:

40mm XYZ Calibration Cube

The original 20mm XYZ Calibration Cube is printed in 8 mins with 0.5mm nozzle at 0.4mm layer height, and so I thought, let’s print it 2x the size with 0.4mm layer height, merely 40 mins later this:

The quality is . . . impressive, this is just tuning a single day – mostly on the extrusion factor and print temperature – and this is what I hoped for: XYZ positioning almost flawless: there is slight ghosting on X axis (which could be resolved) shown on “Y”, and Y axis shown on the “X” which is fine, given the size of the bed and its weight and inertia this is OK.

I had to increase print temperature +20C from 200C to 220C for 80mm/s infill while printing with the 0.5mm nozzle, I otherwise would hear clicking from the extrusion stepper motor missing steps. I still use the classic E3D V6 (clone) heat block, not the Volcano heat block.

20mm Calibration Cube: Different Layer Heights

Printed with 0.5mm nozzle, left-to-right: 0.1mm, 0.2mm, 0.3mm and 0.4mm layer height, 60mm/s (80mm/s infill), 200C first layer, rest with 210C, pink glowing PLA by Sienoc.

20180831_070853

X Carriage: Sliders vs Wheels

While printing with slider carriage on the X axis, I noticed increased stuttering, and regardless if I thighten or loosen the grip, the stuttering remained, and slight horizontal tilt occured when changing direction on the X axis resulting in too narrow prints in X dimension.

X carriage with white nylon wheels (23.mm OD / 7.3mm width)

So, I changed back to wheel-based carriage, first again 23/7.3 white nylon wheels (right photo), but when I printed “L” shape with 200mm length in X and Y and 1mm height in Z, I noticed slight Z sinus form as I saw before – while it rolled nicely, there was a wobble . . . and so I printed a new carriage which holds the black OpenRail Double V (clone) 24.4mm OD / 11mm width, and put it on the X carriage:

X carriage with double V black wheels 24.4mm OD / 11mm width

A brief overview of the carriages riding on 2020 T slot (B-Type) alu extrusion:

carriages-selection

20180905_055421

Sliders: on the X axis it did not last, the stuttering was not avoidable; the issue is that the X carriage is one of the hardest axis of the Prusa i3 style geometry to handle: it isn’t just X directional rail, but also pressure on the Z with the weight of the print head, and running over overextruded filament – and it’s hard to pull the X carriage perfectly without the carriage have some vertical tilt as well – anyway, I still use the slider option on the Y carriage – and works fine so far.

White nylon 23/7.3mm wheel: rolls nicely, but gives wobble to the Z height when used on X carriage, apprx. 1mm, also doesn’t stay vertical upright, but tilts a bit with pressure – when the print head moves over overextruded print it doesn’t level it, but jumps over it. I currently use white nylon wheels on the Z carriage successfully.

Black double V delrin 24.4/11mm wheel

groove use: rolls very nicely, gives no wobble, and stays vertical. The next days and weeks will tell if the double V wheels do last on the T slot alu profiles – they are meant on proper V slot alu extrusions.
diagonal/edge use: rolls very nicely too, but surprisingly gives less tilt rigidity than groove use – the T slot 6 (B-Type) gives less surface at supposed 90deg edge, but is rather 85deg

Z Axis Linearity

As you may have read in the other post(s), I use M6 threaded rods, it’s flexible and rather aligns with the Z axis itself, whereas M8 is stiffer and misalignment – which by the way doesn’t come from the rod itself, but the mounting with the couplers – won’t impose on the X carriage – this is my own view and it happens to come true again with Ashtar K, after I changed my cheap CTC DIY I3 also to M6.

Now, the 1m long M6 threaded rod, enough for two Z axis each 500mm long, did just cost EUR 0.70, made in China but purchased locally in Germany, and the nylon wheel-based Z carriage happen to work perfectly so far – I expected some slight sinus wobble imposed by the nylon wheels as I encountered on the X carriage, but it seems when there is little force applied on the wheel the carriage works good enough.

Printing 330mm high 10mm diameter cylinder (with slider-based X carriage):

There was some slight extrusion inconsistencies, this is ~~likely due the material, an broken vacuum seal of a newly purchased glowing pink PLA roll,~~ actually, after watching the 2nd print closely, either GCode errors or USB transmission errors, as some segments of the circle (layer of a cylinder) is repeated for some unknown reason and so overextrusion occurs there (needs proper investigation) – but the linearity is very good, and no Z wobble whatsoever.

Loopy Egg

60mm height “loopy egg”, printed with 0.5mm nozzle, 0.4mm layer height:

The “loopy egg” is a good benchmark for retraction settings, and stressing the extruder motor as the short segments making up the loops require a lot of push / pull on the filament. There was still some slight stringing, which I knew will happen, as the retraction is just set to 2mm at 35mm/s giving very good results. More prints will tell if I can stay with these retraction numbers.

Fighting Heat Creep

I currently use E3D V6 clones as hotends, one with 30mm “original” fan, and one with 40mm fan. And with the “original” smaller 30mm fan I experienced frequent clogging up within the hotend: some of the filament melted above the heat break and expanded and blocked any further extrusion – that happened now several times.

I tried to reduce the extrusion temperature but which caused decline of print quality. After trying to determine the root cause of the problem, I concluded that it was heat creep and insufficient cooling above the heat break, hence, the hotend fan, and I switched to 40mm fan – ~~and the clogging disappeared~~, not quite yet . . . update follows.

30mm Fan (front facing) with 5015 Fan Fang (top)

40mm Fan (front facing) with 5015 Fan Fang (top)

Although both setups look very alike, I had to print out another fan fang which can contain 40mm fan.

Five Platonics

My favorite geometrical forms – aside the sphere – the sacred set:

Mirror as Bed

I’ve got 40cm x 30cm mirror which became my bed base, underneath with some tight springs some 6mm multilayered plywood, which was warped 2-3mm on the edge – but it didn’t matter (much). The mirror was the reference, and the Y carriage had to hold the mirror. That turned out to work very well: the mirror is truly flat, I leveled the bed once for tilting, after a week, I only had to tweak the Z endstop screw slightly, but I didn’t touch the screws mounting the mirrors to re-level the bed anymore.

So, using the mirror as bed worked well so far due the flatness – but the glass didn’t turn out to print good on it, the printed parts often detached before finishing the print, and ruin the print – so I used blue tape sheet as temporary solution until the black sticker arrives which I already use on the other 3d printer.

Reflection

As I designed Ashtar K with larger build volume, I choose 0.5mm nozzle at least, and the max 0.4mm layer really pays off in regards of print speed, while still maintain some details – I’m quite pleased so far.

3D Printing: Ashtar K: It’s Alive ;-)

by Rene K. Mueller · published August 27, 2018 Technology 2020, 2020 Alu Extrusion, 3D Printing, Ashtar K, Prototyping, Prusa i3, RepRap

Well, after merely 3 months (2018/06/06) when I started to code the first lines of OpenSCAD to develop a series of parametric Prusa i3-like designs, and few weeks ago decided to go with the “K” series with 2020 alu profiles: simple 11x 500mm beam T slot (B-Type) alu profiles – the 1st prototype happen to print the 20mm XYZ Calibration Cube as of 2018/08/27:

: Ashtar K 38.30.33

The bed is very temporarly fasten with tape, as I haven’t decided on the actual details of the bed mounting yet and leveling details – but I wanted to see how well the mechanics already works – and it performed quite well so far.

1st print came out mediocre, when I realized I had to tighten X and Y belts more, 2nd print came out much better; 0.5mm nozzle with 0.4mm layer height, merely printed in 8mins with 60mm/s print speed and 80mm/s 20% infill:

And just for the fun of it, 0.2mm layer height with 0.5mm nozzle, at 70mm/s:

Incredible quality: X and Y surface very good, some inconsistency at “X”, on the “Y” side some slight ghosting; but most surprising is the edges on the Z axis – I operate with a simple M6 threaded rod and M6 nut – that’s all – moving nylon wheel-based carriage up and down – sure, I require to print more tests, in particular larger prints to really see how well all axis print up to 300mm.

I had to use blue tape on the mirror otherwise PLA would not stick – eventually I will use the black sticker as I used for the CTC DIY printer which worked quite well.

Nylon Wheels vs Sliders

The past 2-3 weeks, while waiting the nylon wheels to arrive, I decided to check alternatives such as sliders with PTFE tubes – and this paid off: the nylon wheels 23.0mm OD with 7.3mm width sit quite nicely into the T slot (B-type) but when used in real life, like with X carriage, I had some sinus wobble in the vertical – apprx. 0.5mm to 1mm – way too much. So, I exchanged the wheel-based X carriage with the slider-based carriage, remounted the hotend with Bowden setup, and after 5mins the exchange was done:

: X carriage with white nylon wheels (23.mm OD / 7.3mm width)

Current setup:

X axis: slider-based carriage, holding on top and bottom side with 2 tightening screws
Y axis: simple sliders (just sitting on the groove)
Z axis: nylon wheel (23.0/7.3mm) based carriage

The next days and weeks I will review my options:

slider-based carriage with
- 1 axis support or
- 2 axis support
wheel-based carriage with
- nylon wheels 23.0/7.3 and 23.0/7.0
- double V wheels

both on T slot alu extrusion – I know ideally would be proper V slot alu extrusions, but I like to find out how good it works with the easily available T slot extrusions. Worst case is, I have to use on X and perhaps Z axis proper V slot alu extrusions, on the Y axis it seems the simple sliders (just a block) work fine.

0.5mm Nozzle

Since I deal with nearly 3x the bed surface compared to 200×200 I thought I have to use a bigger nozzle as well, as a bigger build volume would imply larger objects to be printed. The increase from 0.4mm to 0.5mm diameter also implies 1.5x or +50% more material being extruded and I still desire to print with 60mm/s average with 80mm/s infill – this means I have to test well the hotend performs with that speed and higher throughput of material.

Specifications

Current specifications of Ashtar K 3d printer:

380 x 300 x 320 mm build volume (400 x 300 bed)
E3D V6 clone hotend
0.5mm nozzle
Anet 1.0 controller board
210 x 210mm 12V heatbed

TODO

bed mounting & leveling
300×300 or 400×300 220V heatbed
proper print surface (likely black sticker 300×300 or 400×300)
improving cable management:
- Y carriage and heatbed with proper cable chain
- deciding on position of LCD display

3D Printing: Ashtar K Printer: Motor & Belts

by Rene K. Mueller · published August 26, 2018 Technology 2020, 2020 Alu Extrusion, 3D Printing, Ashtar K, Prototyping, Prusa i3, RepRap

Brief update of motors, belts, threaded rods and end stops mounted:

X Axis

I switched from slider based carriage to the nylon wheel (23.0mm OD, 7.3mm width) based carriage (X and Z axis), apprx. 120cm belt length.

Y Axis Belt

Apprx. 90cm belt length – with some considered cutting X + Y ~ 2m belt length.

This part was tricky – the parts are glued to bottom of the wooden carriage:

mark the positions of the sliders (left: 65mm distance from top and bottom, left: center of top/bottom)
glue 2x sliders on the left (where the Y motor is mounted)
glue 1 slider on the right side
put carriage on the rails, avoid any horizontal movement, push it slightly down (a slight snapping you sense from the sliders)
let it rest (don’t touch or move it) for 30min – glue must dry
move Y carriage gently forward & backward; if there is slight resistance then
1. loosen all screws of the right 2020 beam so you can move it sideways
2. then move carriage forward and backward and let the beam slightly find its new position
3. when the carriage moves gently without resistance
4. fasten the screws gently
5. retest and if it’s still resitance, repeat procedure
6. this is a bit tedious work, but worth it

This part is to do next (once I concluded those PTFE pipe chunk based sliders do their job well):

drill holes and use Zip ties to fasten sliders
glue Y carriage belt mount, let it dry
mount GT2 belt to carriage belt mount
fasten Y carriage belt mount with screws: drill holes from the bottom side

: Ashtar K: 3 slider based Y bed

: Y bed mount

: Detail measurements: 110mm from left to slider, 65mm from bottom; stopper, 23mm further, apprx. 20mm aside of slider.

: Slider closeup with trigger for Y endswitch

I will make some short videos of putting the carriage together and mounting it – it’s quite fast to attach and detach with those sliders (no screws to unfasten).

Z Axis

I extended the corner brackets so the Z stepper motors can be inserted, this weakens the part but saves quite a lot of space and hides the threaded rods nicely behind the 2020 Z beams. I might work on those brackets later to increase rigidity again.

: Alu 5mm to 6mm coupler

Currently I use M6 threaded rods for the Z axis, one cycle gives 1mm height change.

X, Y, Z Motion & Homing

Flashing the Anet 1.0 board (which I currently use) with latest Marlin, this was required:

using Arduino Uno R3 (clone), installing Arduino ISP on it
cabling Uno R3 with Anet board (Uno powers Anet board with 5V, all stepper motors or power detached)
installing Bootloader (“Burning Bootloader”) with “Arduino as ISP” as writer
downloading latest Marlin, copying Anet Configuration.h and starting to change it

Finally, after hours fiddling around (bad install of Arduino failed to compile and/or upload anything to my Uno R3) the LCD display greeted with “Marlin 1.1.8” 🙂

Moving X, Y and Z axis briefly, 380 x 300 x 320 build volume with the current V carriage with 23mm OD, 7.3mm width nylon wheels – no extruder and no bed heating and leveling yet.

3D Printing: Ashtar K Printer: Carriages (X, Y, Z)

by Rene K. Mueller · published August 20, 2018 Technology 2020, 2020 Alu Extrusion, 3D Printing, Ashtar K, OpenSCAD, Prototyping, Prusa i3, RepRap, Slider Carriage, Sliders, V Carriages, Wheel Carriage

State: Work in progress

As I finished the frame, I focused on the carriages:

X carriage: moving left to right with the hotend with Bowden setup to keep it light: Wheel-based Carriage
Y carriage: moving bed forward and backward, relatively heavy with 400×300 bed with a mirror to ensure flatness: leaning toward Sliding Carriage
Z carriage: moving up and down with X carriage: Wheel-based Carriage

XZ Frame with X- and Z-Carriages

I made some tests with sliding carriage (composed with PTFE tubes), and finally the Nylon wheels arrived and I began to review two kinds of wheels:

23mm OD, 7.3mm width: even it’s wider it sits better in the T slot 2020 alu extrusion
23mm OD, 7.0mm width: is bit more narrow, but doesn’t sit well on the extrusion

So, I put the 23/7.3 nylon wheel on the V plate to compose a V carriage, and applied to X and Z axis:

Y Carriage

The nylon wheels work very well, given the fine-tuning capability, whereas the sliding approach with 2 axis support (PTFE tubes in sliding direction plus vertical to stay in line) doesn’t give tuning capability.

: 3D printed slider with PTFE tubes

Currently I lean toward the more simple slider (white PLA) with 2 axis stabilization, as with the wheel-based carriage too much vertical force will be applied to the wheel in a perpendicular manner and wear the wheels rather fast.

One of the challenges is to mount three such sliders on the bed – two can mounted quite freely (with margin of 1-2mm) whereas the 3rd slider needs to be mounted very precise.

I update this post as I progress.

3D Printing: Ashtar K Printer: Frame

by Rene K. Mueller · published August 15, 2018 Technology 2020, 3D Printing, Ashtar K, OpenSCAD, Prototyping, Prusa i3, RepRap

State: Work in progress

: 9 beams design

: 11 beams design (more stable)

Building 3D Printer Ashtar K starting with the frame using 2020 T slot 6 alu extrusions, changing design slightly from 9x 500mm to 11x 500mm as early tests showed the XZ frame wasn’t stable enough toward Y bed – so two additional beams (later photos in the series) to make XZ frame sturdy toward the bed.

and the current state more or less:

20180811_152129

While waiting for wheels to arrive I thought to make some tests with sliders composed with PTFE tubes (4mm and 3mm in diameter) – I might actually use them in the X axis and Y axis:

The building volume with the 500mm beams can be stretched to 380 x 300 x 360mm, if the X carriage is short(er) – this means, the bed can be 400 x 300.

3D Printing: Wheels on Alu Extrusions

by Rene K. Mueller · published July 27, 2018 Technology 2020, 2020 Alu Extrusion, 3D Printing, Alu Extrusion, OpenRail, OpenSCAD, Prototyping, Prusa i3

Status: This is a work in progress – and will likely will receive more updates, files not yet released.

Updates

2018/09/14: Added H Plate (4 wheels) and h_plate() reference.
2018/09/01: Added v_plate() variables and numbers for common wheels
2018/07/28: Adding another example with Z axis X gantry adapter & X gantry horizontal beam mount.
2018/07/21: Supporting Delrin R 21.5 or 23mm/7mm wheel as well.
2018/07/20: Version 0.6 added, with ordered mounting holes and nut insets, screw which controls distance inside the plate to reduce overhead
2018/07/19: New version 0.2 with M3 has controlling distance of the 3rd wheel
2018/07/17: First basic design (Version 0.1), few tests made

Introduction

As part of developing various designs around Aluminium extrusions, a few tests. Early tests I printed the wheels in PLA just for sake of testing the dynamics, once the wheels arrived real applications were sought:

20180831_134539

The possible parts are 2020 alu extrusions and Dual V wheel by OpenRail:

: V Wheel

and the “Delrin R” V type nylon wheel (21.5/23mm diameter, 7/7.3mm thickness and 5mm hole):

nylon-weels-s-l1600

Later in the research the difference between 7.0mm and 7.3mm thickness nylon wheels were significantly, as the shape of the wheel differ, and the ticker one (7.3mm) actually sat better in the T slot groove.

2020 V-Slot with Double V Wheels

The V-Slot alu extrusions usage test.

VS_20x20

V Plate (Version 0.6)

Ordered mounting holes (2x 30mm apart horizontally x 2 20mm vertically apart) plus 24mm apart near center, all with M3 nut insets so both surfaces (inside and outside) are nearly flat and mounts easily attached.

Hole-to-hole distance: 40.5mm (20.5 + 20)

2020 T-Slot Diagonal with Double V Wheel

Using the traditional T-slot Aluminium extrusion without proper wheel groove but rotating so the edges are used as rail and the 90 degree inner groove of the Dual V wheel.

2020 Nut 6 B - 999991_1

Version 0.6

Moving the adjuster into the plate to save some space, and adding some insets for the M3 mount holes (2x 30mm apart and 20mm height distance, 2x 24mm apart (Prusa i3 extruder).

Hole-to-hole distance: 47.1mm (27.1 + 20)

2020 T-Slot with Delrin R Wheels

Since the V plate is parametric designed (controlling thickness, distances etc) I thought to support also the “Delrin R” nylon wheels:

V Plate (Version 0.6)

Hole-to-hole distance:

21.5mm diameter wheel: 37.4mm (17.4 + 20)
23.0mm diameter wheel: 38.9mm (18.9 + 20)

V-Slot vs Diagonal

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20180720_175933

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Mounting Holes

Since the V plate, either used with V Slot alu profile or diagonal, has 6 fixed holes with nut insets to attach adapters:

2x 30mm apart horizontally, 2nd row 20mm apart vertically
2x 24mm apart horizontally centered vertically on the plate

An adapter plate or area of 40 x 35mm is guaranteed to be flat, and 5mm thick, with the given mounting holes as mentioned.

v-plate-holes

v-plate-inside

Usage

2x V plates (top/bottom) with its 3x wheels each are made so I can use it as a “V module”:

Prusa i3 Style

X extruder: 1x V module with extruder adapter
X gantry: 2x V module with Z axis threaded rod adapter
Y gantry: 3x V module without adapter, but mounting top V plates direct to Y carriage

OpenSCAD v_plate()

v_plate() takes multiple arguments:

d: distance of holes (-20mm)
h: height/distance of the wheel to plate
orientation: -1 or 1 (back / front)
f: multiplier horizontal distance gap (default: 1)
g: multiplier vertical distance gap (default: 1)

Here for 2020 T Slot B-Type in groove usage:

Nylon wheel 23.0mm OD / 7.3mm width: d=17.2, h=9.0
Nylon wheel 23.00mm OD / 7.0mm width: d=18.3, h=9.0
OpenRail Double V 24.4mm OD / 11mm width: d=22.0, h=5.85

Use

1x screw M3 x 16 with M3 nut (push it carefully yet forcefully so it aligns top/bottom flat) for distance control, put a drop of oil on the tip of the M3 screw before you screw the first time.
3x screw M5 x 30mm with cylinder head with hex inset, and 3 M5 nuts to mount the wheels per double V plate to make up a V module

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Four Wheels: H Plate

For the X carriage with the hotend I thought to add another wheel to improve tilt rigidity (e.g. when overruning bumpy unclean or over-extrusions) – ideally triangle like with V plate/module it’s easy to adjust, four wheels means two wheels need to be adjustable, and those are harder to align properly.

H Plate (Version 0.1)

First version I decided to use a simple solution, have some larger vertical extended 5mm holes and M3 screw which carves its own thread to control the distance – this means the H plate should be used in double to make up a H module, this is the short/narrow 48mm wide H plate:

The plate contains a set of 30mm and 20mm spaced mounting holes, all M3 – requires support from bed only (not “everywhere”) so the M5 nut and screw heads insets are printed nicely for the wheels: