One of the best things about 3D printing is that it lets me work fast enough that I can get an impulse project from concept to reality before I lose the inspiration.
I have had the idea to build a small tracked RC vehicle for ages, but when I came across the Tiny Trak it just wouldn’t get out of my head.
Usually when an idea gets stuck in my head I am forced to scribble it in my notebook to make it go away, but this time that didn’t work and the sketch quickly turned into a CAD model and two weeks later was a printed design sitting on my desk.
This little beastie is 200mm long, powered by two continuous rotation servos, and will have an FPV camera in place of the driver’s head, allowing us to pilot it from the driver’s seat. I’ve designed it to be easy to print and assemble and its small size and low price should make for a fun weekend project.
The beginnings of a plan…
Fusion 360 CAD model
Printed in TitanX Grey ABS on the RoboxDual, the whole design prints without supports.
TitanX ABS painted directly with hobby acrylic paints
The project is now waiting on some electronics, and a design for the driver, stay tuned for updates, and files once they are tested!
Press Release: Launch of an ambitious new UK joint venture challenging established manufacturing methods
5th June 2018
For Immediate Release
Two innovative UK manufacturing companies are excited to announce that they are setting up a Joint Venture called Q5D Technology to launch a disruptive new technology that could change the way products from white goods to cars and aircraft are manufactured. Most of the products that we use today are built by machine, but one part eludes automation: the wiring. This is still done by hand, in distant factories, where nimble fingered workers create wiring looms on peg boards. These are then shipped and fitted, again by hand, into the car or other product. It is expensive, inflexible and time consuming.
CEL-UK Limited is an engineering firm based in Portishead near Bristol. It is expert at the design of equipment for mass manufacture. They make and sell highly regarded 3D printers under the Robox® brand. Chris Elsworthy the Managing Director explains “By combining existing technologies we are making a new breed of machine that is able to create polymer parts with embedded wiring and electronics of any shape that can an assembled autonomously as part of the manufacturing process”.
M-Solv limited is an Oxfordshire based high-technology company which makes machine tools for the rapidly growing printed electronics market. “This new technology will be able to make lighter, cheaper, more complex components that will enable engineers to go from concept to product much more quickly” explains Phil Rumsby the Managing Director of M-Solv.
Stephen Bennington of Krino Partners Limited “These two companies each have unique technology as well as the depth of experience and access to the markets that will ensure that this new venture will be a success”.
Notes to Editors C-UK Limited
CEL-UK has considerable experience and expertise in the design of tools for mass manufacture. They started by designing and selling award winning power tools, but now they are best known for the Robox® series of 3D-printers. These machines pack innovative technology in a beautifully designed and easy to use product that would cost many times more from any other manufacturer. They have expertise in mechanical, electrical and software design as well as mass manufacture.
Contact: Chris Elsworthy (Managing Director) www.cel-uk.com
M-Solv is a world leader in printed electronics and laser micro-machining. They design, manufacture and sell highly innovative machine tools, but also do contract R&D and mass manufacture printed electronics components.
Contact: Phil Rumsby (Managing Director) www.m-solv.com
Krino Partners Limited
Krino is a consultancy that provides assistance to UK technology start-ups. Stephen Bennington is a visiting professor of physics at University College London but has spent the last 8 years running and/or assisting technology businesses with planning, interim management and fundraising.
Contact: Stephen Bennington (Director) www.krinopartners.com
CEL is a 3D printer manufacturer based in Portishead near Bristol. We design and manufacture very highly regarded 3D printers for home and business use.
We have a new production line which uses CNC machinery to create a new line of 3D printers. We need staff to build and test these large 3D printers before they are sent to our customers.
There are several positions available which could be filled at an entry level or by people experienced in fabrication and assembly. The finished items are complex but the assembly process uses simple steps to build the units from well designed parts. This new team will have direct input to engineering and design decisions so is a great starter for someone wanting to get into or advance their skills in mechanical design and engineering.
You will need to be:
Capable of using typical hand tools safely with competence.
Willing to learn and carefully manage the use of new tools such as a CNC machine.
Excited by mechanical concepts and technology, wanting to know more.
Interested in growing with and building our locally owned company.
Able to work with small and large items. The completed 3D printer weighs around 20kg.
There is a lot of opportunity to grow within CEL, following pathways to business technical support, local and international sales, engineering design and management of any or all parts of our business.
We are very proud of our products and want our team to feel the same.
Typically we work regular office hours. Hoping for full time but this can be negotiated as we have a lot of work and may hire several people into similar roles.
We would like to hear from students who have just finished studies and experienced people who can help us reach our goals. Pay and rewards will vary per experience and will grow with responsibility. You must be eligible to work in the UK, no agencies.
In the last post we got a working differential together, since then I have been designing the axle tubes, axle shafts and the drive shaft.
I have mentioned from the beginning that I am trying to keep the complex mechanical components compatible in size with off-the-shelf RC components, so I have made the width of the axle and the mounting points exactly the same as the Boom Racing SCX10 axle that I used on my rat rod build.
Printable rear axle with differential compared to Boom Racing SCX10 axle for size
The housing of the differential has been redesigned so that all of the tolerances are contained within one part, and the cover simply screws down on top, holding the two largest bearings in place. Nothing has an overhang more than 45 degrees, so it is all printable without support.
The differential housing and cover shown in their print orientations.
New housing holds whole assembly in place far better than the previous clamshell.
Inside the axle tubes there are two bearings which support the printable axles shafts. The axles shafts have provision for an M4 rod down the middle, which provides both strength and the opportunity to use standard RC wheels if desired.
Section shows the internal structure, especially the M4 rod which transmits torque to the wheels as well as allowing them to be attached
One tube removed, exposing the axle shaft, drive cup, bearings, and 12mm hex
Complete assembled differential, axle tubes and cover are held on with M3x8 screw
I printed and assembled prototypes based on this design and it went together well. My plans to test immediately were delayed due to some mistakes I made in the sizing of my driveshaft, but the assembly feels satisfactory when turned by hand, I have high hopes for the first test!
The assembly, printed in ABS filament
Stay tuned for the assembly and test video of the rest of the axle shortly, as well as work on the drive shaft and universal joints.
Robox AutoMaker software update is now live. Start your AutoMaker installation to find the update automatically or download it from here www.cel-robox.com/downloads/.
Your firmware will need to be updated as requested by the software, please note that the Robox will restart when the firmware update completes so be sure it has finished printing before allowing the update.
When you connect a Root or Mote device it will require an update to be able to communicate with AutoMaker, this will be shown as a button in the Network menu in AutoMaker preferences page.
Support for RoboxPRO
Support for SingleX head
Macro improvements across pre and post print along with maintenance functions
Major overhaul Root UI and backend to improve connectivity and transfer
Lots of functions added to Root
New SmartReel profiles and fixes surrounding programming locally and via Root
Linux settings page fixed (was blank)
Translation UI issue fixed
Reprint functions improved
Hardware warnings for abrasive materials dependent on head fitted
Lots of small changes to improve UX
A big welcome to our new software developers Tony and George, this is the first AutoMaker update they have worked and is just a small step on the path toward a lot of new content.
Over the past few weeks, with a brief hiatus due to international travel for my day job (I’m an Electrical Engineer in the telecoms industry), I have been plugging away at the design of the rear differential.
I have a few design goals for the rear axle
Approximately the same size as a “standard” 1:10 crawler axle (both to make this re-usable in other applications and to make it possible to use a commercial axle on this build)
Functional open differential
Accept standard RC wheels with a 12mm hex drive
Rugged enough gears to handle, at least, a “silver can” 540 motor
Look fairly realistic (not too important in this build since it will probably be hidden)
Preferably printable without support
Of course the rear axle can be made significantly smaller (or stronger, in the same envelope) if we go from a open differential to a spool, which will be a suitable modification if it is to be used on a rock crawler.
I first attempted to design from the outside inwards, starting with my goal diameter for the differential and designing gears to fit inside it. This turned out to be a bad idea, causing endless redesign, it was much more sensible to design the gears and build the casing around it.
There are other aspects to keep in mind, almost all of them relating to tolerances. For example, if a bearing recess is part of the face that contacts the printer bed then the slight bulging can prevent the bearings from fitting.
Designing Bevel Gears
Unfortunately Fusion360 doesn’t have a decent tool to create parametric bevel gears and designing them properly yourself is no mean feat. This is a real nuisance because we have to import gears from elsewhere and then design around them.
Fortunately there is a very nice script written for OnShape which you can find here and it is not too much trouble to set them up as you like, export as STEP files and import into Fusion360.
In order to keep my design “semi parametric” I positioned all of the gears sensibly with respect to the origin, and then defined variables which correspond to the gears dimensions. So long as all of the dimensions of the housing correspond to these variables and aren’t referenced to the gear objects themselves it is fairly easy to swap the gears out with others.
This iteration of the design provides another approximately 2:1 reduction, which means that we should be able to shrink the transmission that was designed in the last post.
Differential Mk III sectioned
Differential Mk III closed
Differential Mk III exposed gears
Rapid Prototyping – Use It!
This is more of a personal lesson, but perhaps it is worth reminding. If you are like me then you design something to 85% and then realize that you could have designed it better, then you repeat the process, without ever printing anything. With something that takes 100’s of hours to print that may make sense, but for tiny parts like this it is just foolishness. There is a lot to be learned by just printing the item, and trying it out as is.
These are pictures of the first functional assemblies, hastily printed in ABS (not printed on a Robox, I look forward to seeing how well it handles the small pieces though!).
Mk I – Test Print
Testing the mesh of the sun and planetary gears. The screw used as an axle will be replaced with a smooth shaft.
Test assembly shows that the design works, but there is too much play in the side gears.
Here the M3 screws which hold the assembly together are visible, but it is also clear they will interfere with the bearing.
Complete functional assembly, despite a few tolerance issues it works perfectly
Print orientation should always be considered in the design phase.
Video: Assembly and Test
Some things are best expressed in video, and assembly is one of those things, so here we go!
Our Robox 3D printers and the CEL UK-based support team have been superb. Students of all ages, from our primary school partners to Post-16 students, have all been able to access and use the Robox software and hardware systems effectively. They have inspired students and led to numerous STEM Big Bang competition wins. Further to this, our work as a community Fab Lab has allowed organisations and individuals to develop ideas on a personal level or commercially.
The Robox technical support team are second to none and offer excellent training materials to ensure systems are kept up and running. CEL are always keen to support users with emerging applications of their machines and illustrate their forward and positive principles.
I would recommend Robox to any educational establishment looking at purchasing 3D printing systems.
For a great deal of parts such as the steering wheel plate and the brake pot hanger, the only alternative to Robox would have been folded aluminium. Not only does this increase the chance of the parts being incorrect, but it would have cost around £150-£175 for the steering wheel plate, and £75-£100 for the brake pot hanger, both with a 2-week minimum lead time.
Contrasting with Robox, the steering wheel plate cost £2.66 and was ready to fit in just over 3 hours. The brake pot hanger cost £14 and took 10 hours to print, which again is much cheaper and faster than any alternative.
Additionally, we find that in many cases, 3D printed ABS parts are also more aesthetically pleasing than folded aluminium, and seem to suit the nature of our cars. For example, the switch box design would not have been possible in aluminium; it would have simply been a folded sheet with wires protruding out the back. Not only is there a safety aspect involved, but the ability to create a sealed box with all wires and connections hidden looks much better than a folded metal sheet. Again, this is achieved with costs being reduced from around £60 to £5.37.
For parts such as the rain light cover, the only alternative to Robox would be injection moulded plastic, or carbon fibre. Again, these options are unfeasible, as both would cost hundreds of pounds. With Robox, the component cost £2.95, and was complete in under 3 hours.
Most of the tooling we manufacture is used to remove wheel bearings, etc. These tools are usually fairly intricate and cost in the region of £300-£400. With a trial piece printed to test fits, usually for under £0.50, we can be sure that these tools will be correct.
Overall, in the past year I would make a conservative estimate that by using Robox, we have saved at least £3,000 and reclaimed around 2 months of lost build time in comparison to alternative methods.