3D Printing: Ashtar K Printer: Motor & Belts

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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:

  1. mark the positions of the sliders (left: 65mm distance from top and bottom, left: center of top/bottom)
  2. glue 2x sliders on the left (where the Y motor is mounted)
  3. glue 1 slider on the right side
  4. put carriage on the rails, avoid any horizontal movement, push it slightly down (a slight snapping you sense from the sliders)
  5. let it rest (don’t touch or move it) for 30min – glue must dry
  6. 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):

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

 

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.

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)

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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.

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

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State: Work in progress

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: Sliding on Alu Extrusions

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State: Early draft, work in progress and likely will receive updates.

Updates

  • 2018/08/15: Added Slider with PTFE tube inlets with 1 and 2 axis support with photos and brief test video
  • 2018/08/05: First overview with a 3 approaches

While waiting for the shipment to arrive, I thought to study some of the alternatives to wheels on alu extrusions, such as sliders.

2020 Nut 6 B - 999991_1

Nylon 2020 Slider

gleiter-glatt-b-typ-nut-6_3Commercially manufactured, apprx. cost EUR 2.50 per piece, sold in 10 pieces bag.

 

 

 

 

 

3D Printed Sliders

Simple Slider

A simple replicate of one of the simple 2020 sliders:

The sliding nose is 5.8mm wide. Ideally this would be printed in nylon; PLA might work as well but tends to stick more and grease or oil is required therefore.

TODO

  • print samples and measure friction with PLA
  • publish model

Slider (2 Sides) with PTFE tubes

Improving the simple slider with 10mm long 4mm PTFE chunks to decrease surface and use proper material for sliding:

screenshot-from-2018-08-15-06-21-23.png

and in use for the Y axis of a Prusa i3 like style:

20180813_084627

and a small improvement to take care of the 2nd axis as well (reducing 2nd axis wiggle):

Screenshot from 2018-08-15 06-21-15

20180817_102329

and then mounting them with a carriage together with M3 screws to control tightness:

and a brief test:

Slider (4 Sides) Carriage with PTFE tubes

A bit more complex using PTFE tubes on all 4 sides:

each inner side has 8 tube chunk insets, which gives you the variable option:

  • 4 chunks (a 10mm) x 4 sides = 160mm total
  • 8 chunks (a 10mm) x 4 sides = 320mm total
  • 12 chunks (a 10mm) x 4 sides = 480mm total
  • 16 chunks (a 10mm) x 4 sides = 640mm total

The OpenSCAD module takes parameters such as length of the carriage and the diameter of the PTFE tube (e.g. 3mm or 4mm), default length 60mm.

And the adjustable version with 75mm width looks like this:

which breaks the one surface apart with the mounting hole; if a plate would use all 4 holes that side would become non-adjustable that way – so this isn’t ideal, but perhaps work for single side use.

A possible application as X carriage and two Z carriages in a Prusa i3 use case:

printer-ak-with-sliders

TODO

  • print model and make actual physical tests, measure friction of the possible options
  • publish model

 

 

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3D Printing: Wheels on Alu Extrusions

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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:

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

20180720_175909

20180720_175933

20180721_194709

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:

  1. d: distance of holes (-20mm)
  2. h: height/distance of the wheel to plate
  3. orientation: -1 or 1 (back / front)
  4. f: multiplier horizontal distance gap (default: 1)
  5. 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

20180831_134523

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:

h_plate() settings – same as for v_plate():

  • 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, h=5.85

For the short version, width=48 (less won’t work).

Examples

Extruder/Hotend Adapter

Attaching E3D V6 hotend on a pair of 30mm holes with M3x8 (M3x10 might work as well) with M3 nuts (in this example printed in purple PLA):

Z Axis Adapter

A simple Z axis adapter, here with M6 threaded rod with M6 nut:

The adapter is 4mm thick, and M3 x 10 should work (in this example I used M3 x 16 which are too long, but still work).

X Gantry Horizontal Beam Mount

A small simple piece to mount the 2020 horizontal X axis on Z axis V module:

Additional holes to fasten beam with T nuts as well (top and bottom of the bridge).

V and H modules used as part of the Ashtar K 3D Printer:

printer-ak-vplate-closeup

20180830_174653

20180915_191015

Related Projects

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3D Printing: Fixing Z Banding

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Using a low-cost 3D printer like CTC DIY I3 Pro B (Geeetech I3 Pro B clone) with M8 threaded rods as Z axis with loose or floating ends is what you get – and so also some wobble or banding on the X axis due slightly bent M8 threaded rods – they barely come straight. I hesitated to use lead screws due decrease of resolution (M8: 1 cycle = 1.25mm height, lead screw like TR8x8 (8mm dia, 4 starts, 2mm pitch, 8mm lead => 1 cycle = 8mm height) but otherwise gaining pretty straight lead.

Anyway, I searched Thingiverse for Z mounts for the CTC DIY and found a few, and adapted one design and made a remix Geeetech / CTC Prusa i3 DIY – Z Axis Bracket Remix with printable Bearing:

  • changed structural holes (larger hole -> smaller holes)
  • bearing hole widened to have more floating
  • printable bearing added to restrict end (optional)

New Z bracket mounts (black), without/with printed bearing (white):

20180712_13470020180712_150437

And I did a few tests:

20180712_200705

Left to right (close-ups photos below):

  1. original Z bracket (wood) apprx. 4mm play
  2. new Z bracket without printed bearing, apprx. 10mm play
  3. new Z bracket with printed bearings (with loose tolerance)
  4. new Z bracket with printed bearings (tight tolerance)

Now comes the surprise, the best surface (best to worst):

  1. no bearings / open floating: gives the smoothest surface, most straight Z edge
  2. tight bearings: gives very good surface, slightly worse than with no bearings
  3. loose bearings: noticeable artifacts / wobble, Z edge wobbly
  4. original bracket: worst wobble of all, Z edge wobbly

Which means, either give it a lot of space so the upper end of the Z threaded rods can float, and thereby the X gantry can stay fixed (and not wobble) – or – fix the threaded rods and suppress wobble (there is still wobble but restricted).  Giving it some space on the top means the inherent wobble of the rod is distributed between top and X gantry – giving wobble artifacts on the print . . .

The issue isn’t simple: with or without fixation gives good results, some fixation gives more bad print results.

Open Ends / Floating

The new Z bracket provides more space for the threaded M8 rods than the original wooden bracket:

20180712_134700

Printed Bearings

You may print two bearings (OD 22mm, ID 8mm), make sure to test inner diameter, so the threaded rod slides smoothly – if required use a 8mm drill to widen the inner hole.

20180712_150437

Conclusion

Worst Z wobble was with original Z mount with ~4mm play or the loose bearing with apprx. 1-2mm play.

Best results I achieved with floating ends or with tight bearing – in other words, either leave it open or make it stay close, but worst is to give it a little play and threaded rods will show their unevenness on the prints.

I would also guess, the unevenness of the threaded rods and their position to each other also matters, e.g. whether left and right go the same way or cancel each other wobble out. What I noticed was, once I used the printable bearings for a print, and removed it, the threaded rods wobble already less – but as said, best results I achieved with no bearing and wide floating ends or with the tight bearings.

Recommendation: print the mounts, print the two bearings, and print the XYZ Calibration Cube or whatever reference item, and see yourself which option works better for you.

Addendum: M6 Z Axis Conversion

I made a small package Geeetech / CTC DIY I3 Pro B M6 Z Axis Conversion to use M6 threaded rods instead of M8. It made little difference:

  • less wobble, but still wobble despite of “straight” M6 threaded rods
  • wobble seems mostly introduced by the couplers (either printed or PVC pipe):
    • out of center alignment = wobble
    • tilted mounted rods = wobble

It is hard to mount the rods perfectly with the couplers, a little misalignment and one introduces wobble (X/Y wiggle).

Anyway, M6 gives slightly higher resolution in Z axis with 0.005mm per motor step.

3D Printing: Layer Height

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Printing with different layer heights with the same nozzle diameter (e.g. 0.4mm) gives quite a range of printing quality and printing time – the higher the quality or lower the layer height the more printing time it takes, the 20mm height XYZ Calibration Cube as an example:

20180711_193114

0.05mm layer height / 398 layers / 1.38 hrs

0.1mm lh / 200 layers / 0.73 hrs

0.2mm lh / 100 layers / 0.37 hrs

0.3mm lh / 66 layers / 0.25 hrs

0.32mm lh / 62 layers / 0.23 hrs

0.32mm layer height is 80% of the nozzle diameter, and supposed to be the maximum of layer height.

0.14mm – 0.39mm lh / 64 layers / 0.21 hrs

using the Adaptive Layer Height feature of Cura.

0.4mm lh / 50 layers / 0.18 hrs

obviously too high layer height with 0.4mm on a 0.4mm nozzle, some layers have gaps.

0.4mm w/ 0.6mm nozzle / 50 layers / 0.11 hrs


using 0.6mm nozzle on E3D Volcano clone – not quite tuned with under extrusion on the top (90% flow, with 100% flow the X/Y surfaces were terribly over extruded).

All printed with

  • 60mm/s print @ 190C
  • 80mm/s infill
  • 150mm/s travel
  • 1st layer: 20mm/s print @ 200C

on

  • a heavily improved CTC DIY I3 Pro B (Geeetech DIY I3 Pro B clone) with
  • Bowden setup and E3D V6 clone hotend,
  • sliced with Cura 3.4,
  • printed with white PLA-R (recycled PLA) by Fabru – it was a custom extrusion based on recycled white PLA, they usually sell only black recycled PLA as of 2018.

While reviewing all the samples, I noticed I could improve the Z banding issue, which still showed a bit – addressed in 3D Printing: Fixing Z Banding; done after all my layer tests.

Conclusion

Layer height 0.05mm and 0.1mm look very alike with this XYZ Calibration Cube – so it’s not really worth 0.05mm but 0.1mm would be sufficient. The Adaptive Layer Height turned out quite well, near the same speed as 0.32mm layer height.

The top surfaces of 0.05mm and 0.1mm are very nice, whereas 0.2mm already shows significant artifacts – best choice would be to print the last layer at 0.1mm layer height.

If one prints large volume, it’s worth to consider a larger nozzle, e.g. 0.6mm nozzle diameter, which outputs 2.25x more material already yet direct drive recommended – I struggled with complex prints with retractions with the Bowden setup.

I usually print at 0.2mm layer height, and if a larger piece is required I increase to 0.3mm – for the future I might switch the Adaptive Layer Height feature in Cura in that case.

3D Printing: CTC DIY I3 with E3D V6 Clone Hotend

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E3D-V6-J-editedThe CTC DIY I3 Pro B, a Geeetech I3 Pro clone, is the very low-end of 3d printers – quality and pricewise, and uses a direct drive to feed the filament aka “MK8 Extruder”.  I ordered an E3D V6 clone with 0.2mm-0.4mm short nozzles with optional Volcano hotend for larger diameter nozzles (0.6mm – 1.0mm) from China, at EUR 9 price, as I wanted to

  • print faster, above 100mm/s if possible
  • print thicker or larger layer height to reduce print time for larger volume prints, e.g. 0.6mm – 1.0mm nozzles

and E3D V6 hotend seemed to be the remedy.

First I tried the Bowden setup, then printed an adapter so E3D V6 works with original extruder as well, e.g. direct drive is recommended when printing with flexible filament.

2-in-1 Fan Setup for E3D V6

20180604_172725

I used the 2-in-1 fan duct: extruder and filament cooler for E3D V6, it’s low complexity and low mass makes it quite suitable, yet, since only one fan is used, it cools at the first layer already and likely reduce adhesion – not optimal but for now an acceptable compromise. The cooling otherwise is excellent, as good as my “duck beak” fan I had with original setup.

To secure the fan better, I used some rubbery-like glue (when dried) and put it on the end of the clamp of the fan adapter (let it dry first before using), to increase the grip on the hotend – as the fan once fell off while printing when it ran off failed printed filament which was cool and hard already – which would have caused quite a chain of dangerous events (hotend no longer cooled, melting the mounts, falling on the heatbed and heat whatever lies on the bed if the print(er) would have let be unattended).

E3D V6 Radial Fan Fang

20180721_143402After some time I switched to E3D V6 Radial Fan Fang, which uses 5015 radial fan, which turns on at 2nd layer – I used a remix which uses 40x40x10mm fan for the heatsink and replaces the small E3D V6 fan.

If you choose this, file the grip a bit so it attached smoother to the heatsink – my first print broke while attaching.

 

Quality of E3D V6 Clone

e3dv6-cloneBefore I go into the details, let me comment of the overall building quality of those E3D V6 clones: you get what you pay for, a compromise. My hotend leaked like crazy, at the junction of heatblock & nozzle, and heatblock & heatbreak – which is most annoying, and that did not happen with the original MK8 Extruder.

Remedy: I used teflon thread tape used to seal threads of the heatbreak, on both nozzle and heatbreak thread – this is really suboptimal. The teflon thread melted over time (not right away but after days/weeks), so I didn’t keep it.

hotend-problemUpdate 2: the real problem of leaking was the PTFE/teflon inliner, the end toward the nozzle wasn’t perpendicular sufficiently and likely a bit too short (by less than 1mm) and it was too narrow tube with 3mm OD instead of 4mm and be more tight – so the PLA leaked between the inliner and the threads of the heatbreak and nozzle – so the real remedy is to pay close attention of the length of the inliner (in case the E3D V6 clone comes without it as in my case), and give it 0.5mm to 1mm extend with a clean cut and preferably a conic end which presses then toward the nozzle.

Further, I had to use again a teflon inliner/tube – this wasn’t an all metal hotend, means, I am still limited with limited material choices, staying below 240C to preserve the teflon tube.

But on the upside, the quality of the extrusion was excellent, there was an significant improvement of print quality compared to the old “MK8 Extruder” setup, and I seemed to increase printing speed as I desired:

E3D V6 with Original Extruder

20180604_171258

I used an adapter but altered it so it prints without support Simplified E3D V6 mount for CTC Prusa i3 Pro B with original extruder, fortunately it maintains the similar Z and Y distance to the bed as the original hotend, so there is little to change.

And the usual XYZ calibration cube at 60mm/s and 120mm/s:

Since I didn’t upgrade or customize my firmware yet, my thermistor likely reported wrong temperature, as the possibly new type wasn’t properly assigned in the firmware – and I had to reduce print temperature, too much stringing otherwise occured:

20180604_200117

The tests reveals that stringing is mainly a problem of nozzle temperature, and much less of retraction length.

XYZ Calibration Cube

Left to right: 60mm/s, 120mm/s and 150mm/s:

Surprisingly it still performed quite well with 120mm/s and 150mm/s, although I doubt 150mm/s were really achieved at this small print.

E3D V6 MK 7 Extruder Settings

  • Printing speed: 60mm/s – 150mm/s
  • Infill speed: 100mm/s – 150mm/s
  • Motion speed: 120mm/s – 150mm/s
  • Retraction distance: 1.5mm

E3D V6 with Bowden Setup

With the Bowden setup one uses a teflon/PTFE tube to put the extruder motor stationary aside and push from there, reducing the moving mass on the X axis and so faster printing speed is possible – but as I found out, with faster printing speed more pressure in the hotend and if the hotend isn’t properly sealed, it will leak quickly.

20180603_061944

The first run with Bowden setup, the extruder stepper motor not yet mounted but sitting aside:

With the direct drive I printed at 60mm/s as default, now printing at 80mm/s the XYZ Calibration Cube:

and the results are impressive, left 60mm/s, right 120mm/s:

20180603_061929The two E3D V6 bowden adapters I first printed and used required quite some change in Z height, bringing my Z stopper screw to its limits and also were off in the Y axis – so I designed a more suitable adapter with multiple mounting holes: CTC Prusa I3 Pro B E3D V6 Extruder Adapter V2.2 with a simple extruder motor mount at the top left-hand side of the XZ frame.

E3D V6 Bowden Settings

  • Printing speed: 60mm/s – 150mm/s
  • Infill speed: 100mm/s – 150mm/s
  • Motion speed: 120mm/s – 150mm/s
  • Retraction distance: 2.5mm – 4mm (really depends on the length of the Bowden tube)

Conclusion

Using E3D V6 with a low cost and low quality 3d printer:

Faster printing with improved overall print quality.

Aside of the leaking, which was fixed with teflon thread tape, the E3D V6 clone is a great addition to the CTC DIY I3 Pro B – true added value, but comes with more cumbersome handling with sealing threads when exchanging nozzles.

Btw, in this setup I still use M8 threaded rods in the Z axis, and you see no Z wobble artifacts, the linear threads for the Z axis are overrated – it works with simple M8 threads, if you let the couplers flexible enough, like with this “cheap” clear PVC tube, and not fasten the threads on the top, they have to stay floating.

3D Printing Experiences: 60 Days Later

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Video ID not provided: Please check your shortcode.

Some further notes using CTC DIY I3 Pro B 3d printer the past 60 days:

Sample Prints

Propeller Guards

Printing propeller guard at 60mm/s (first started with 40mm/s and then “Tune” -> “Speed” changing from 100% to 150% when I saw first few layers went well) with Kaisertech white PLA @ 210C:

This is quite a hectic print, a lot of motion of the head and relatively narrow infills; 20% infill, 0.3mm layer height with 0.4mm nozzle.

Sphere

I really like, admire the Platonic Solids, and Johnson Solids, and there is the Sphere – the ultimate archetype of form – and for sake of challenge, I tried to print a 25mm diameter sphere – without support (with it, you won’t get a smooth surface).

20180518_161102

The trick which worked, was printing a brim and 50um layer height with slow speed of 15mm/s at height 0-4mm height and then 30 mm/s for the rest, that allowed to print the slope at the bottom of the sphere somewhat, not perfect but good enough for now – I will keep refining the process though.

Many Failures

Additional, my one-side blowing part fan showed its weakness, there is a cooling “shadow” (1st photo below) which shows when printing small objects where the nozzle reaches the same point soon and insufficient cooling is happening: the printing curls up, and causes bad surface in the final print.

Cura has a special mode called “Spiralize Outer Contour” and it prints circular with a steady increase of Z, smoothly, yet, without infill, the top won’t work (2nd photo), and the bottom was very weak that it broke when I tried to remove it (3rd photo).

A simple way to print a smooth sphere is to break it in two halves, and print both hemispheres and glue them together.

Challenge 1st Layer

The first layer is the challenge in 3d printing, because it can fail based on various reasons:

  • not well leveled toward X gantry (level it)
  • dusty surface (clean up)
  • uneven bed itself (use glass)
  • uneven bed while heating up (level in warm/hot bed state)
  • uneven bed while hot (let it in hot state for a few mins and level again)
  • bad filament (change it, keep records)

and I discovered another reason:

  • inconsistent extrusion because of
    • missing steps (clicks) of extrusion, too low temperature (increase temperature of extruder +10C)
    • bad teflon tube (replace it)
    • partially jammed or clogged nozzle (clean it or replace it)

which is hard to determine: one has to observe the first 3 layers closely and if it’s laid down “nicely” (even surface), and see if the width of the laid down filament is consistent, if not and it varies then the filament tends to curl on the nozzle instead to lay down to the bed.

I was in the process printing ~100 pieces, in 12 pieces batch prints, after 5 batches and the first layer failed after 10-11 pieces and I had to abort the print for 10x in sequence (re-level and cleaning bed and otherwise determine the problem) until I realized it was the worn out teflon tube, after I replaced it the following prints worked well again.

The past weeks I discovered the hotter the filament, the more likely a good first layer, but you have to print the next layers a bit cooler, otherwise the final surface come out smooth. So, with Cura you can set “Printing Temperature Initial Layer” and increase +10C to the normal printing temperature.

CTC DIY Bad Print Reasons and Remedies

These are the issues I encountered the past 60 days:

  1. two screws which hold the “L” with the extruder on the X axis, they tend to get loose and X motion will change Z level, or give bad layers once in a while when it tilts – retighten those two screws
  2. nozzle gets loose with time giving bad quality prints (e.g. after a few weeks), retighten in hot state (at 215C for example), not too tight
  3. screws and zip ties of the Y bed get loose giving bad quality prints – remove heatbed and rethighten all screws if necessary and retighten or replace the zip ties
  4. recheck X belt tension and Y belt tension
  5. recheck Y motor holding, best fasten entire Y motor at the back with zip ties
  6. refasten screws which connect XZ frame with Z motors
  7. recheck the teflon tube whether malformed or has residue (replace)
  8. clean the nozzle with a fitting drill (e.g. 0.4mm) or cold pull

Changing Filament

Push/pull method:

  1. preheat nozzle (with LCD Controller manually, or with Cura) to 215C for PLA
  2. push manually the filament into the extruder ~2cm firmly, if it goes easy then do 3), if not, wait for a few seconds, and push again (it has to go easy)
  3. swiftly pull out the filament – most of the times the break will happen below heater block; a few times a thin break happens which blocks the extruder wheel
  4. push in new filament manually and push old filament out the nozzle until new filament shows up
20180515_173254

Just for the fun of it: seamless (without interrupting printing) changing filament

Continually or seamless change PLA filament:

  1. preheat nozzle (with LCD Controller manually, or Cura) to 215C for PLA – or you are in the midst of an existing print job
  2. cut perpendicular (not pointy) filament few millimeter above the extruder
  3. cut perpendicular new filament (not pointy)
  4. extrude more filament (with LCD controller or Cura) until old filament disappears into the feeder
  5. insert new filament so there is a seamless continuation of filament (too much force screws up Z layer height, too little force doesn’t take up the new filament)
  6. hopefully the new filament pushes the old one nicely through

Improving CTC DIY Prusa i3 Pro B

Replacing Pulleys

After some hesitation, I replaced the white plastic pulleys and printed pulley holders for the new GT2 metal 16 teeth pulleys, also for the X and Y motor, with the existing bearings (MF85ZZ: 8mm outer diameter, 5mm inner):

 

I printed a small washer (in white PLA) (8mm outer, 5mm inner, and 2.5mm thick) so the pulley would stay more centered and not move or wobble like the older/original pulley holders.

Replacing Y Bed Bracket

Quite an obvious move, when you look at the way the bed it attached with the Y belt it’s not parallel, and I felt this will interfere with precision in Y axis in general – so I used this CTC Prusa Y Belt Holder / Bracket to replace it:

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And now the belt is parallel to each other and the smooth rods and threaded rods as you can see.

Stabilizing Y Bed on XZ Frame

The Y bed is just fastened at the back and in the middle with the XZ frame, and it’s quite wobbly – so I tightly fastened with two more M10 nuts and washers.

Note: Although the upgrade looks simple, but it is not: when you fasten the M10 nuts on the XZ frame, do this while the printer sits properly on a table (which is cumbersome) – fastening the nuts in another position will results in a skewed geometry of the printer (happened to me at first).

After this upgrade most flimsyness of the frame has vanished, which otherwise this 3d printer is known for.

Cooling the Extruder

CTC did a sloppy extruder construction: when you look closely you see a small black screw holding the heating screw but also doesn’t allow the cooler seamless attach the aluminium block – there are several remedies, I choose to give the screw a bit space by drilling a small dent into the cooler (you know where to drill as the screw likely has hinted the position already):

So now the cooler makes good contact to the aluminium block which transfers the heat of the extruder/nozzle.

Replacing Fan Blades, Adding Fan Covers

20180511_194617

I broke one of the fans and I tried to replace it. Unfortunately to remove the old fan blades is a tricky thing and I broke the fan – the proper way is to remove the label at the back, push the blades on the other side so the pin comes out where the label was – and remove the ring coming out – this allows to remove the blades from the fan.

To secure the blades better, I printed two fan covers for those 40mm x 10mm fans, one for the extruder fan, and one for the part fan.

20180515_123708

Further, the fast X axis movement doesn’t do good on the fans – and so just after 2 weeks with the new part fan cooler, it already makes noises when starting up – as if the initial tilt of the fan being in resonance and not able to achieve full speed; a gentle tap on the fan cover brings it out of resonance – this isn’t a good solution though.

Z Motor Stand

20180520_124738It bothered me at the very beginning, and finally resolved it: the Z Motors are lifted 8mm in air with a bracket, the force from the XZ frame and the smooth rods is distributed between just three screws, whereas the most tear is just on one screw – it’s fairly simple to make some stand so the entire Z motor takes some weight as well and adds stability.

Download the STL of the “Z Motor stand” at thingiverse and print it yourself.

Y Bed Cable Chain

The past weeks I noticed the narrow bending of the cables at the Y heating bed and it eventually will break there. So I searched on Thingiverse for some solution, and I found Cable Chain with a nice cable chain element:

Note: You must mirror both mounts (left <=> right) – within Cura use the Mirror Tool –  the mount on the side (CTC_Y_base_mount.stl), and the mount on the bed (CTC_Y_bed_mount_bottom.stl) – because the original setup is meant for the left side, but if you do that you have to switch the back planes of the Y bed to move the Y stopper switch on the other (right) side, but you can avoid this by mirroring both mounts before you print them.

The cables of the heat bed and termsistor were sufficient long to be wired via the right side, and then below the bed to the left side where the controller board resides.

Update: I moved the cable chain mount up ~1cm on the side and not reuse the screw which holds the power connector but drilled a dedicated hole – which makes the cable chain fairly horizontal now.

Documenting XYZ Cube and other Prints

One of my habits is to document things properly through time so I can fine-tune things I did already and review changes, in particular with 3d printing, using the 20mm XYZ calibration cube, writing down

  • date
  • printing speed [mm/s]
  • filament brand
  • extruder temperature [C]
  • infill [%]
  • layer height [mm]
  • special features (e.g. brim, raft, etc)

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It helps me to review:

  • whether my changes on the printer increased or decreased the printing quality
  • whether filament from the same source but different color have different settings
  • whether filament quality decreased due my own storage

Software Tools

Mostly I use

  • OpenJSCAD.org, a local copy of it to be precise (offline), whenever I have a common theme or functionality, when special features become functions and things a composed programmatically,
  • OpenSCAD.org, the known scripted CAD approach, and
  • for WYSIWYG-like I use TinkerCAD.com for quick and simple models (online) but save all models as STL as backup.

For Linux users, as viewer I use

  • MeshLab (apt install meshlab) and ensured it’s the primary application for .stl files – for Ubuntu 18.04 LTS you have to edit /usr/share/applications/meshlab.desktop, ensure “%f” is added in the “Exec=meshlab” line:
[Desktop Entry]
Version=1.0
Name=MeshLab
Name[en_GB]=MeshLab
GenericName=Mesh processing
GenericName[en_GB]=Mesh processing
Comment=View and process meshes
Type=Application
Exec=meshlab %f
Icon=/usr/share/pixmaps/meshlab.png
Terminal=false
MimeType=model/mesh;application/x-3ds;image/x-3ds;model/x-ply;application/sla;model/x-quad-object;model/x-geomview-off;application/x
-cyclone-ptx;application/x-vmi;application/x-bre;model/vnd.collada+xml;model/openctm;application/x-expe-binary;application/x-expe-as
cii;application/x-xyz;application/x-gts;chemical/x-pdb;application/x-tri;application/x-asc;model/x3d+xml;model/x3d+vrml;model/vrml;m
odel/u3d;model/idtf;
Categories=Graphics;3DGraphics;Viewer;Qt;

and I installed the STL thumbnailer for Nautilus (GNOME default file browser) as well:

Screenshot from 2018-05-12 21-03-19

 

From now on I will post smaller blog posts more focuses on particular issues, and tag them with “3d printing” and alike.

3D Printing Experiences: 30 Days Later

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After 30 days after receiving the CTC DIY Prusa i3 3d printer, here some notes of what I did:

Sample Prints

I choose the “easter eggs” series as designed by Antonin Nosek as sample print to tune and review my machine settings (extrusion flow, nozzle temperature, printing speed) and compare the quality of the results:

For now I used “Sienoc” branded PLA filament (purple, black) which performed well (adhesion, printability), “Kaisertech” white PLA which was OK, and a collection of 20 colors of PLA of unknown brand each 10m for smaller prints (required 215C instead of 200C).

  • “Voronoi Loopy” egg stresses the 3d printer with short segments, stringing issues will show up if temperature is not well tuned (much stringing, likely too high temperature, increase travel speed)
  • “Plain” egg I used for general temperature setting

Here are few brief video samples of printing pieces at difference challenges:

Easter Eggs

The easter egg “minecraft” version on the lefthand side usually requires support to print the overhangs, but at 40% size (~25mm height) with sufficient cooling at the nozzle/part extrusion it prints properly without support, printed at 60mm/s (black PLA by Sienoc @ 200C).

Easter Egg “Voronoi Loopy”

The easter egg “Voronoi Loopy” is a bit of torture for the 3d printer, as the layers are chopped into many very small segments which in 3d form many loops covering the surface. It’s printed at 0.2mm layer height and 60mm/s printing speed, but since it’s printed at 0% infill that speed is not reached – black PLA by Sienoc @ 200C.

Bathtub Plug

A friend required a fitting plug for a bathtub and I quickly made a small cylinder or rather cone with two different radius. Since it was used in outdoor and forcefully inserted, I printed it with 30% infill and 0.3mm layer height (with 0.4mm nozzle) and 80mm/s printing speed to save time, printed with black PLA by Sienoc @ 200C.

LED Strip

I already added a white LED nearly the nozzle, which highlights the immediate printing areas but I wanted to have good light for the overall printing – so I added a LED strip along the inner XZ frame.

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Bed Surface

Using original blue tape strips eventually gets ripped and damaged with a lot of printing and I ended up replacing it. At first I tried to put entire blue tape sheets on the bed, but those worked terribly: the tape was so adhesive to the printed parts, that the tape ripped easy from the bed, and some tape remained on the parts bottom even.

As next I’ve got a stickable printing surface, which worked very well at first but after a few prints had hard time to get a good first layer regardless at which bed temperature, the filament didn’t stick well on the surface but curled among the nozzle.

Currently I used the black stickable surface and blue tape sheets on top, until I found a better solution.

  • Black Stickable Surface: at first worked good, but then had unreliable 1st layers often – it seemed to me it’s more critical to the bed leveling, too small or too big distance and the 1st layer will fail, and filament curl on the nozzle.
  • Blue Tape Sheet: PLA sticks (too) well, but rips from the bed when removing the part; unless you wait the bed cools off down to 20C, but for larger parts with a lot of area at the first layer, I ripped off the sheet from the bed.
  • Blue Tape: the original tape worked very well, the PLA sticked well and very tolerant to bed leveling, and printed parts were able to remove easily – large 1st layer area one has to use a tool to left the parts; with frequent use the tape loses some of the adhesive quality of the prints.

Networked 3D Printer with OctoPrint

20180506_182205I used this guide to add OctoPrint to Orange Pi Zero, and used the 3d printable case I developed for OP Zero to mount the device to the frame.

To use OctoPrint with Cura:

  • enable the OctoPrint Plugin within Cura (“Plugins” -> “Browse Plugins” -> “Octoprint” -> “Download” and restart Cura then)
  • “Printer” -> “Manage Printer” -> click on “Connect OctoPrint”
  • enter IP, API Key (visit OctoPrint direct in your browser, and “Server” -> “API Key” and copy) and paste API Key in Cura:Octoprint
  • it will look up API Key and give “OK”

As next instead of “Print to USB” it will show option “Print with OctoPrint” in Cura.

Fastening Y Motor

I noticed that the Y motor mount wasn’t really well fastened and those two tiny M3 nuts worked themselves into the wood – a disaster waiting to happend – and I replaced the mount and used two zip ties to firmly mount the motor to the back plane – just in case.

Additionally I printed an Y Motor mount (read the comments there) or alternatively this version might work as well – as another spare one.

That’s it . . .