Wednesday, June 15, 2016

"IvorBot", the early days...

I found some short videos of early days testing of my core-xy movement (stacked, fishing-line, rectangular format). Worth sharing I thought, as even a short video shows so much more. In the first clip you see it plot, probably doing about 40mm/sec. It was my first experience of a core-xy movement and was pleasantly surprised at how precisely it plotted, and how accurate the repetition of the same drawing was. Fitting a pen holder to an x-carriage is always a practical way to get an initial feel for movement and dimensional accuracy, in x/y directions at least. See video below.
(In the audio you can hear the poor quality groove bearings beginning to grind, which was it's ultimate downfall. The stepped nature of the circle is just the way it was drawn.)

Driving it at higher speeds didn't help the failing bearings, but you could really open the throttle on this chassis. Having no weight at all on the x-carriage helped. In this other short video clip (below) you can see the movement running at faster speeds. I used an old Gen6 board to drive the experiment, which it did without issue once I updated Marlin firmware for the core-xy support. The tests were controlled from Repetier Host. If you don't have an extruder fitted and want to trick the printer into working you need to set a dummy thermister "998" in Marlin Configuration.h, and un-comment #define DUMMY_THERMISTOR_998_VALUE 185". You can then slice something and send the gcode file, which it will pretend to print, or plot if you have a pen fitted, and no Z mechanism.

I learned a lot from this 'prototype'. I was able to draw on my existing body of knowledge and understanding of 3d printing, and build on that to construct this experimental chassis. The plans were drawn up in Sketcup primarily, which I use quite a lot for design visualisation. With some plug-ins I can export for printing (STL), and export for laser cutting (SVG).

I've also found Autodesk 123D very good also, and move to it for more complex components.

By building the physical working model I was able to get a true sense of scale, construction challenges, and mechanical performance. I was then able to modify design and rapidly improve through iteration, swapping out both printed parts and laser cut framework. I'm constantly keeping an eye to my primary design goals of compact size for given print volume (200x300x250 approx), along with dual extrusion capability with room for experimentation.

More detail of the journey to follow.
Tks for viewing.

Sunday, June 12, 2016

Code named "IvorBot"! (Part 1)

I've been lax in blogging of late. Sometimes it seems there's always "just one more thing" to do or make or print before a new blog post is worth writing. Then the weeks and months pass and the motivation to post historical work just isn't the same after a time. Lets see if I can do a bit better on the blog front going forward!

I'm always keeping an eye on 3d printer developments, innovations and direction, as things continue to evolve at some pace. Digesting these influences, I've regularly found myself subjectively noting the 'desirable' and 'best' features of the changing printer vista, with one eye, as always, on building my next printer.

A design is always given focus with some constraints, and for my "next printer" I imposed some goals that formed the general basis of the prototyping and experimentation that followed, for some time now. Key enhancement objectives included such goals as faster print speeds without loss of print quality, dual extrusion, moderately larger print volume, but minimum increase in outer printer dimensions. Secondary goals might be a flexible carriage system to allow for easy print head swap-outs for greater flexibility.

The choice of movement system and filament feed mechanism was left open in the early research. Also, I wanted to explore and experience bowden vs direct drive, 3mm vs 1.75 and the pros and cons of these now common machine choice variables. My new printer would give greater opportunity for testing and learning, reconfiguration for experimentation.

The attractions of CoreXY has stood out for some years, and has enjoyed much adoption in both experimental machines and commercial printers of late (FABtotum, Airwol3D Axiom, SmartrapCore). I quickly settled on this as key design feature and pushed on with some basic pland.

Armed with Sketchup, my trusty Mendel90 and access to a local Fab Lab laser cutter I was quickly able to stand-up a basic core-xy chassis. For a fast and relatively accurate movement system I also took inspiration for RichRap's use of Spectra line as in his Sli3RD Printer, and even Nicholas Seward's CoreXZ printer. The following fishing line CoreXY "plotter" was put together (Photo below.).

Using fishing-line allowed compact and flexible "belt" paths. By routing the line over small groove pulleys it was possible to position the motors below the x/y plane resulting in space saving and more compact external dimensions. (Illustrated in photos below)

Access to a laser cutter was transformative in terms of flexibility of chassis design, manufacture and build speed. It allowed me to iterate quickly, and a very low cost. I worked in Shetchup, exporting to SVG via a plugin for laser cutting comparability.

Above is one of my printer frame work revisions being cut from cheap plywood on the Trotec laser cutter at Fab Lab Limerick. Back at home (below) the next revision was quickly constructed and motion testing resumed.

The prototype printer, pictured below (actually just a plotter at this stage), made many trips to the Fab Lab - Thursday evening sessions over the Winter, for peer review and valued feedback. It was during one of these visits that it earned it nick name, the "IvorBot", which has stuck!

Testing with the fishing-line core-xy chassis ran it's course. It was functional and with the addition of an extruder might even have done some printing, but it didn't have the robustness I was striving for. Also, my choice of cheap grove bearings was a mistake and they were grinning and failing as I'd push the speed and tension on the fishing-line. 

The next major revision of the design was a move to belt drive, and brass pulleys. I designed and printed a whole new set of motor mounts, corner brackets and x-carriage ends. I chose 9mm GT2 belt, matching brass pulleys with double inserted bearings, LMS8UU linear bearings. I ran a "stacked" cord-xy belt path so there was no cross-over in the design. I felt the wider belt and pulleys wouldn't lend itself to the cross-over belt path that typified some core-xy layouts.

Another frame was cut, this time with more z-height, and when E3D started selling the 200x300 heated bed from their BigBox printer separately, I jumped at the opportunity and matched printer frame size to accommodate this larger print bed.

Above, "IvorBot" current revision. It prints reasonably, but there were many changes to get it to this stage as you might appreciate. I recently got it tuned up for dual colour printing, which was a new personal mile-stone, and gave me the incentive to resume some bloggin. There's lots more detail to share, and much planning going into changing and refining my design, but for now I'll sign-off and get this much published.

As always, comments and questions welcome!

Wednesday, May 27, 2015

A day out for my Mendel90!

I'm involved locally (Limerick, Ireland) in a maker group, that has both a virtual presence (  ) and meets once a week in Fab Lab Limerick The formation of this group has been a great way to meet other makers in the region, and the level of activity has grown steadily over the past year, perhaps much to the determent of this particular blog, but with an invitation to speak about our maker group and fab lab, at an innovation day hosted by Dell Solution Center, Ireland, I thought it would be worth sharing a few photos here on my blog also.

It was an excellent opportunity to take my Mendel90 out-and-about. As always the printer got lots of attention and questions. A few photos of the event are featured on our maker FB Group page , some of which I'm reproducing here (Photo credit to Lucia in the maker group)
Prints in the foreground are by one of our maker group members, Dara, (medical illustrator)  (on an Ultimaker 2). There's an interesting musical instrument by Ed Devane , in the picture also, which he calls a "pluck wheel lute". It's utilised in instrument building music workshops he runs. He makes some parts of the kits in the Fab Lab. 

Talkin' the talk, at Dell Solution Center, Limerick, Ireland.

My Mendel90 printing Heatwave Vase from here: Always a good show print!

Thanks for viewing!

Sunday, February 8, 2015

Minor updates to my printer (Mendel90 scratch build)

Quick post showing some minor printer updates I've made in recent times:
Moving to the newer Mendel90 x-ends, with their 4-screw bar clamps, has made a good difference to my printer. The older design, (second photo below) was unable to clamp the bar tightly enough and I was loosing belt tension over time. The clamp was also beginning to split along layer plane. The newer design doesn't have this issue as the layers are in compression because of the clamping direction.
Newer x-end installed above. Nophead relesed this design back in Oct 2013, and has been incorporating this design in the kits he sells since then, but if you have an older printer it's worth updating. Full detail on this and other design improvements he has made to the Mendel90 can be found here: 
This is the older x-end design, with it's weaker x-bar clamp arrangement.

I'm trying out an E3D V6 hotend at present, swapping it out for a J-Head which, by the way, I've never had an issue with. I just want try some printing in some materials that require higher extrusion temperatures, beyond that supported by the J-Head.

 To mount the E3D Hotend on Mendel90 without loosing any Z-heignt, I took inspiration from the hot-end clamping idea devised by Ralph Hilton which he shares here: I applied this hot-end clamping approach to Nophead's original extruder, importing the original STL into Sketchup and hacking away there until I got it as I wanted it. It's not pretty, but anyone is welcome to the Sketchup original if you think it's of use. (just give me a shout on the RepRap Forum under user name NumberSix).
Screenshot of extruder modified to clamp E3D V6 hotend in a way that does not result in loss of Z-height. The keen of eye may also observe I've moved the left extruder clamping hole. I want to be able to attach/detach the extruder to the x-carriage without having to remove the E3D fan assembly so have also made an x-carriage with an enlarged hole. See screenshot below.
X-carriage with wider opening to allow E3D hotend to be inserted/removed without taking it's cooling fan off, or detaching it from the extruder block. (one in picture not in my current colour, just test printing it)

One thing leads to another, and if you swap out the j-head (on a Mendel90) for an E3D hotend you'll soon realise the original work cooling fan doesn't fit over the larger heater block of the E3D. So that lead me to Daniel Bull's Fan Duct  which he drew in in Autodesk 123D Draw. A fine job he mad of it too, but it's distance below the x-carriage is set for the E3D fitted to an original (M90) extruder and in a much lower position.
The screenshot above shows my modified version of Daniel's fan duct. I've lowered the mounting points, and adjusted things to make room for the x-belt. It was a struggle but a good way to learn more about 123D Design. Daniel provides a great starting point in his shared fan duct. I added the little cross you'll see in the middle of the duct to help with bed adhesion on this narrow circle. The cross is cut away after printing.

That's it for now! Thanks for viewing.

Saturday, November 15, 2014

TCTShow 2014 (Part II)

In sorting through my gatherings from the TCTShow (2014, Birmingham, England) there were another few bits I thought worth sharing. At this stage you will find comprehensive round-ups of the show on Rich's Blog, and for a view of the high-end machines do see Christopher Barnatt's excellent review here, but I had a few picts of my own to add.

Active3D's X1 on the left, RichRap's Sli3DR printer on the right.
If you like the make/build aspect of this world then a closer observation of the many printers on display at the shows is certainly worth while. For instance, the two machines above have something interesting in common. They both use Spectra fishing line instead of belts, one on x/y, and one with line on x/y and z! The print quality from both was excellent, which just shows that while not commonly used, the Spectra line is a practical alternative to belts.

And there was this curious configuration at the excellent Ooznet stand... looks like a Prusa i3, which it basically is, but fitted with an unusual extruder driving mechanism, called a Flex3Drive! It allowed the best of both worlds, the light x-carriage with the motor remotely, but still the benefits of direct drive extrusion (lower retract distances). It worked very well.

This lovely looking delta, by Andrew Wade drew lots of attention. It's a self-build which Andrew is working towards releasing.
This desktop sized filament maker was in the show's Start Zone. Called the "Strooder", it received it's start-up funding from a Kickstarter launch in June '14 and is hoping to do it's bit to reduce filament costs to consumers by providing a way to make your own filament from pellets, which are a fraction of the cost.

This prototype experimental hopper extruder design was on display by RichRap. At a desktop level, the whole concept of directly feeding plastic pellets is quite at it's infancy, but has exciting potential to reduce cost and offer interesting blending possibilities right at the printer.
Above, RichRap's prototype pellet extruder.

I'll rounding up with two short video clips...

The Nectar One wasn't quite ready to print at this years show, but gets the prize for the coolest door opening mechanism in the show! I wish them well in their launch.

The fastest moving mechanism at the show has to be the cutting blade on the Mcor IRIS printer! (See video below). 
3d landscape printed on the Mcor IRIS.

There's a bunch more photos which I'm going to push to a Google+ album for general viewing at this point. It's probably the handiest way to share them out. Link here.

Thanks for viewing!

Sunday, October 5, 2014

The RepRap Community Hub experience at TCTShow 2014...Part 1

To truly gain new experiences you have to step outside your comfort zone. I knew I was doing that when I informed RichRap on the RepRap Forum, that I’d be willing to help out at the RepRap community hub at this year’s (2014) TCTShow in Birmingham, England. I had no idea how amazing an experience this would actually be!
Above, RichRap and one of his amazing creations, the Sli3DR in the background.

For me, one of the simplest satisfactions would be in helping and interacting with community members and visitors to the show. The side benefit would be the opportunity to meet some of the legends of the 3d revolution, the “virtually famous” of the RepRap world! Sad, I know! :-)

Also, having observed and experienced the rapid development and evolution of desktop 3d printing from a virtual and remote perspective for many years, I felt it was time to engage in a more real way. What better way than to fly into Birmingham and participate in what is now becoming an annual gathering, the RepRap Community Hub at the TCTShow!

(Above, Chris and Mary Palmer, of Mendel90 fame, working on Huxley90, and lots of vases!)

For sure there would be more to gain from interfacing directly. You can’t beat face-time for knowledge and experience exchange, and I knew the opportunities would present themselves, if all I did was show-up!

Having scratch built my own Mendel 90 over a year ago now, it was indeed an honour to meet the team behind the design, Chris and Mary Palmer (Below). With my silly t-shirt on, the ice broke quickly and the rest of the show was filled with gems of wisdom from Chris and good humoured banter and fun from Mary!
During the show, Chris worked quietly on a small machine in his area. but what had gone mostly unnoticed and without fan-fair was that we were witnessing the first public viewing of a brand new printer. To the passer-by it looked like another of the many many printer designs to be seen at the show, but to the 3d print Anoraks out there this is actually a portable version of the robust Mendel90. Chris indicates he's calling this one the "Huxley90".  It will offer the performance and reliability of the Mendel90 but combine it with portability, for those times when you just have to bring your printer with you! Expect to hear much more from Chris on this one.
(Above, Mendel90 and Huxley90 side by side.)

Have you ever made a copy of yourself? It's the latest in "selfies". It's a peculiar experience and worth doing once. I was tickled when Justin Carpenter of Active3D offered to scan and print me. It gave me a chance I've been looking for to explore the process and assess the workflow of scan to print. Justin made the operation of the hand-held scanner look easy, and I'm sure with a bit of practise anyone could manage it. He used a consumer level scanner called the Sense. It has encouraged me to research scanning in more depth, as I think ease of input is a great enabler to 3d printing work.

Head tilted back so no support needed. Printed in wood filament for good matt finish. One of the first things I printed when I got home was a second copy of myself. Good fun!

You just don't know who you are going to meet! I was introduced to Mark Drubin (MakeALot on Thingiverse),  an accomplished designer and user of OpenSCAD, a gentleman and another of the virtually famous of this 3d printing world! Check out his work...

The people... the prints... the machines... There are so many photos worth sharing that I just had to do collages to publish them more quickly! Have a browse!

Quite honestly, between all the exhibitors, the volume and quality of printed examples was facinating. So many to admire, examine and enquire about. Below is just a small flavour, and just too many to individually credit, so if you see your creation below, thank you for sharing!
The myriad of desktop sized printers was equally fascinating.

Hopefully at this point you have a small insight to my experience at this event! If I continue with a single post it's likely never to get published, so I'm going to hit "publish", and return with further posts to explore many more topics that interested me and are related to the show, such as:

3d printing/printers in schools/colleges. 3d content and the education sector.
Next year... how can the Community Hub be improved? Become a better experience for visitors?
What's happening on the filament front.
Is there diversity or convergence going on at a desktop 3d printer level?
The hot-end space...
New kids on the block... Nectar, others.
Who visited the RepRap Community Hub and what type of questions were asked.
Other stories from around the exhibition... as I occasionally wandered around, each stand and encounter had it's own story! I'll try pull some examples together!

Thanks for viewing. More to follow!

Saturday, September 27, 2014

3d printed Limerick City Model unveiled...

FabLab Limerick recently unveiled a scaled architectural model of Limerick City, Ireland. It's a most amazing model, faithfully reproducing the Georgian grid and architectural detail found centrally in the city. It's a living model which will continue to grow over time.

The city was surveyed and photographed extensively, and the arduous task of painstakingly drawing each building and city block was undertaken over the past few months. The work was conducted by graduates of the School of Architecture at University of Limerick. The FabLab is run by staff, students and graduates of SAUL.

Blocks of builds were prepaired and printed on a selection of 3d printers, including RepRapPro Mendels, Mendel 90, and Ultimaker2 printers. Below is a small selection of photos from the recent open evening at which the city model was unveiled. The base board was CNC cut from digital maps to accurately reflect the city terrain, incorporating another digital fabrication process available in the facility. The model remains available for public viewing at the FabLab.

I'm sure we will hear more about this fantastic undertaking and achievement!

I had the honour of being asked to help out with the printing. The blocks practically filled my print bed and ran from 8 to 12 hrs print times. Printed in PLA, a layer height of .2mm was used on the city prints through-out. This brought out fabulous architectural details that were captured in the fresh drawings of these buildings. After printing a few of the city blocks I found myself examining buildings and city streets with a new eye in recent days! It showed me detail around the city I had never noticed. Printing parts of the city and scrutinising other printed blocks has been a fun and enlightening experience!

Thanks for viewing.