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 to the fresh drawings of these buildings. After printing a few of the city blocks I found myself examining buildings and city streets with new 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.

Tuesday, September 23, 2014

Scaled 3D print of "ShopBot" project...

While learning how to use a ShopBot CNC router I was looking for a suitable starter project and came across the very popular Patio Chair project on the ShopBot site. It quickly occurred to me that I could assess quite a lot about the design simply by scaling and 3d printing the necessary parts. The conversion to STL file for slicing and printing was relatively straight forward, and is summarised below. I've broken down the steps, aiming the post at Sketchup beginners.

The downloadable drawing was in .DXF format and easy to view in a 2D drawing package such as DraftSight.

My starting point was to import the .DXF into Sketchup so I could use the Push/Pull tool to give each part some depth for printing. I first had to install a Plug-in into Sketchup to enable importing .DXF. There's a well known plug-in called "FreeDXF" which I found would only work with older versions of Sketchup than the free 2014 version I was using, but with some further digging I found I could manually install the plug-in by adding the files manually to the following location... (Windows7)
The plug-in still gave an error when starting Sketchup until I edited the "freedxf.rb" file, replacing ":" with ";" to clear up a minor issue.

When you import a DXF into Sketchup the shapes come in un-filled. This is easily fixed by drawing over any existing line. The part then turns dark grey, showing it is manifolded (no gaps), and ready to be extruded (push/pull tool). To remove internal shapes repeat the "draw over" process, then select the internal shape and 'delete'. There are probably plug-ins that can do this clean-up more quickly but, again, this walk-through is aimed at beginners. 
Selecting the Push/Pull tool, extrudes all parts to a depth of 3/4" to match the material specified in the original CNC cut design. If you have Sketchup set to millimetres you can still specify Imperial dimensions and it will conveniently do the unit conversion for you. Push/Pull to any distance, then simply type .75" and it will take the 3/4" distance and apply it.

To match the original wood design the joints need to be blind dog-bone pockets. Push/Pull the pockets to a depth of 1/2", matching the tenon depths on the chair sides. 
The final preparation step is to scale all parts down to a size that will fit on the 200x200mm print bed. This is best achieved by selecting all, then using the Scale Tool, drag one of the green corners of the yellow box inwards any distance, then type .15 and hit enter. This will scale all objects down to 15% of original size, to fit nicely on a typical desktop 3d printer.
Select and export the finished pieces from Sketchup in STL file format.
Because of the small pockets and little tabs on the objects I found it needs to be sliced at a reasonably high resolutions. I used .2mm layer height with a .3mm width in Slic3r, but you can choose your own slicing software and settings. The important thing is to preview the g-code to ensure you are getting good definition around the pockets and little tabs. Repetier Host is good for g-code preview, as is the on-line previewer If you experience any difficulty slicing then I find the Cloud based Netfabb STL repair service very good (, Service... Cloud Service). 

Here's a picture of the printed plate of parts. There was a little but of clean-up needed to be done around some of the tabs and pockets, but overall the parts printed well.

The chair was easily assembled with a dab of super-glue in the pockets and the parts pushed together, checking for square are you go. A trial dry fit is always a good idea too.
The finished miniature Patio Chair is proving to be a novel and popular item. Full credit TJ Christiansen who did the DXF drawings for ShopBot, and to ShopBot for sharing. The design was said to be found on and originally from American Woodworker Magazine. I'm sure it goes back a long way, and was made with traditional methods long before CNC or 3D printing!

Technical note: The parts were printed on a home made Mendel90, controlled by a Panucat Azteeg x3. It was printed with 3mm PLA using a .5mm J-head nozzle, active cooling on the J-head insulator and gentle cooling on the work. I use a glass print surface, cleaned with window-cleaner and a final wipe with vinegar. I have a Helios heated bed, which I set to 60Deg C for PLA printing.
The chair was sliced in Slic3r at .2mm height, and around 50mm/sec, but a much slower first layer.

I've shared my Sketchup and STL files on should you wish to try print this chair yourself. 

Thanks for viewing!

Monday, September 8, 2014

RepRap Community Hub and this year's TCT 3D Printing Show...

I'll be helping out at the RepRap Community Hub at this year's TCT 3D Printing Show in Birmingham, UK. It promises to be a busy and exciting 3 days! Looking forward to it!
Show Floor Plan

Further detail on RepRap Community participation in this years show on this RepRap forum post here.

Wednesday, July 2, 2014

Choice of slicer for hollow printing...

People occasionally ask me which slicer I use... the answer really is "it depends". It depends what I'm printing. Over time I've found that different slicing packages are good at different aspects of printing. A good example of this was when I tried printing this Worldcup Trophy. It's quite a large object and some reported it taking up to 6hrs to print and consuming around 10m of filament, even with a relatively low infill percentage. I felt printing it hollow was the best approach. This would considerably reduce the print time and material consumed and should be achievable.
Worldcup Trophy, standing about 22cm high including Alzibiff's base.

From experience of different slicer programs I've tried out, I've found Ultimaker's slicer "Cura" to be the best at printing hollow objects that close in at the top. When you slice a large object with Cura and set it to 0% infill it 'scribbles' support material on the inner walls when the walls close to a shallow angle as it nears the top. It can be seen as brown lines in Cura's Layers View Mode (below).
This additional sidewall support works well and allows a hollow object to close in completely without any internal infill or internal support construction. The successfully closed in top of the trophy print can be seen in the picture below. The print is hollow.

To complement the trophy, a nice base was designed and shared by Alzibiff, incorporating some nice raised text. I printed it in contrasting green and gold by simply "guesstimating" the length of green needed for the first part, then feeding some gold, then feeding some green to conclude the print. If the print rate is slowed down, as is possible with the speed slider control in Repetier Host, it's possible to watch the cut filament disappear into the extruder then manually feed the next colour into the extruder by hand until the hobbed bolt grips the newly fed filament.

One point of note if you are trying out Cura to slice for a RepRap printer is that Cura calculates Extrusion distances in "absolute" measures, where as RepRap printers generally expect "relative" extrusion distances. To accommodate this simply place an "M82" command in the Start.gcode section of Cura. M82 makes the extruder interpret the extrusion as absolute. M83 sets relative extrusion.

Thanks for viewing!

Tuesday, April 29, 2014

Makers Meetup... local Fab Lab event.

A recent local Makers Meetup brought a broad mix of skills and interests together, with talks from the worlds of photography, graphic design, ceramics and 3D printing.

Fab Lab Limerick promoted and hosted the event. The general aim was to ensure a presentation mix of creative and technological disciplines, to stimulate thinking, and discussion amongst the group, and explore how the different disciplines might complement each other. It was an interesting and enjoyable evening.

(Above) I spoke on the topic of 3d printing, focusing on how more accessible it's becoming, and showing many examples my 3d printed work. It was enthusiastically received and generated many questions from the group.

(Above) David Hunt, a keen photographer and Raspberry Pi exponent, showed how he has combined his interests by building a motorised time-lapse rail controlled by a Pi board. There are some great examples of 'time-lapse in the Irish landscape' on his website... , well worth checking out.

(Above) Claire Jordan, a local ceramic artist, talked about her work, and how engaging with the Fab Lab has helped her explore new directions. With help from the Lab, she's currently exploring the methodology and potential of 3d printed 'cookie cutter' style tools, as productivity aids for some porcelain ornament design lines she has in mind.
Above is one of the experimental 3d printed hand-tools Claire has devised in cooperation with staff at the Fab Lab.
Lucia Poliakova and Mariel Mazan, recent Visual Communications graduates, talked about how they have utilised the Fab Lab resources such as the laser cutter/engraver in creative ways, as they get their new design agency under way this year. The Lab is an invaluable resource in support of new start-ups, bringing creativity, technology and knowledge together with very positive results.

Finally, I brought my Mendel90 along on the evening and demonstrated it in action. It drew much interest. The Lab has some 3d printers as part of it's tool set, and has plans to add more printers soon.

A big thanks to Javier and Michael at the Fab Lab for hosting the event and providing the photos for this blog post.

Thanks for viewing!

Wednesday, April 23, 2014

New Fab Lab opens locally...

Some local news worth sharing for the Irish readers of this blog. Limerick, Ireland, sees a new Fab Lab location launched recently.

There's a Makers Meetup event at the Fab Lab location (7 Rutland Street, Limerick, Ireland) on Thursday 24th Apr 2014. I'm bringing my Mendel90 along, and giving a short talk on my experience and the ever increasing accessibility of 3D printing. I'll also show some printed items, and engage in a bit of Q&A. Promises to be interesting.

I'm delighted to see the establishment of a local Fab Lab, giving a focal point for meetings, events and perhaps workshops. I look forward to meeting other 3D printer enthusiasts from the region, at the location over time.


Sunday, December 8, 2013

Santa Sleigh...Ho Ho Ho!

It's that time of year when we turn to printing Christmas things! The range of published designs seems to grow and grow each year.
This year I took sleigh parts from various sources and combined them in to a new Santa and Sleigh combination (above). It's made up of sleigh runners from the CreativeTools Sleigh, which I separated from the sleigh body for easy printing. This also allowed these parts to be printed in a different colour to the sleigh body for a nice contrast. The sleigh body was re-drawn in Sketchup by simply extruding a profile which matched the gaps in the runners (side parts). I then recessed a seating area within the sleigh body, to give Santa somewhere to sit!
(Above) Parts laid out in Sketchup. There's a left & right runner because it's not a uniform thickness.

The reindeer were from Chefmaki's Sleigh, a sleigh I printed last year (see here). The deer were imported into Sketchup and scaled up to match the new sleigh size.
(Above) Six reindeer print nicely in one go, along with the supporting bar. 200mm x 200mm print bed.

I trawled for a suitable Santa to sit in the sleigh and settled on this one (photo below) which I extracted from this Candle Holder using Meshlab, tidied it up in SketchUp and sliced in Cura. Cura has a neat feature which sinks an object into the platform, creating a flat bottom on the base of an object so it sits well. Support was enabled for the arms and hat.
The sleigh body (red part above) was printed on it's side. The top wall needed support when printing in this orientation. Removing support material can often be a challenge, and the ease with which support material breaks away can vary greatly between slicing software, and settings chosen. For this project I found Kisslicer had the best support material and the easiest to remove, but you may have your own favourite. I chose a coarse Support setting with a .2mm horizontal gap. I've included a short video (below) of removing the support material from the sleigh body, for anyone that might be interested.

Once all the elements were printed the runners were glued to the sleigh body, leaving the body recessed slightly for best effect. The reindeer were attached to the support bar, all with dabs of super-glue. The final touches were added with some embroidery cord for reins and plastic gems for the reindeer. 

This is a nice Christmas Ornament and can be printed in many colour combinations and decorative styles.
 Version above with gold sleigh and red runners.

Files published to Thingiverse:

Technical Notes:
It is worth trying different slicing software when printing new objects, as they all seem to have their own ways of plotting the print. In the case of the narrow swirling sleigh rails, I found Cura performed the best, filling in the gaps between the close perimeters of the rails very neatly. Both Slic3r and Skeinforge left gaps in the narrow rails, even after much experimentation with settings.

A .3mm layer height gave a good finish for all the elements of this print. The reindeer had a 25% infill. Anything less risked the top solid horizontal layers gapping or dipping. Santa was printed with hollow, giving a nice translucent look with the gold filament.

The above was printed in 3mm PLA, to a heated glass bed with a light PVA/water coating on the glass. Nozzle tempeature of 185Deg C, bed temperature of 60 Deg. (if using a Prusa HBP you may need the bed temperature set slightly higher because they are typically fitted with the heater on the underside, and there is a 10 to 15 deg difference between the underside and the top of the heated bed.)

 I use a .5mm j-head hotend, with active cooling on the PEEK, and variable speed cooling on the work. The printer is a scratch build Mendel90 (not from kit).

Happy Christmas printing!