3-D printing of e-bike parts
Some weeks ago I received an invitation from materialise, Europe's largest commercial 3-D printer, to participate in a 2-day workshop at their headquarters in Leuven/Belgium.
I was intrigued. Rumors have it that the Belgians print whole railway stations in 3-D, like this one in Liege...
Liege/Belgium railway station
Just kidding, but who knows what might be possible in the future.
The introductory workshop was tailermade for manufacturers, and was aptly named 'Your serial production with 3D print'. Present were representatives of major car manufacturers, aircraft & medical companies as well as a well-known Design company. And me.
We heard specialists in their field explaining us the various methods and their applications. We were shown around their factory, and had a look at their production facilities and their exhibition rooms. If this is where manufacture is heading, I'm in. Sadly, no pictures were allowed to be taken.
The workshop endet with the participants being split into 3 teams, and the task was to designing new products with new technologies, guided by their engineers. Funnily, all products ended up bicycle related.
Before going our own ways again, we all were presented with training certificates.
materialise 3D Academy certificate
How I got involved with additive manufacturing
I had been playing around with 3D print for some time. The reason were stiff prices for a CNC-machined plastic housing for a single prototype, about € 200.
After some research I landed on the materialise homepage, offering a web-based prototype service. Since I had a 3-D model file, I uploaded it and asked for it to be laser-sintered in PA-GF, a PA12 based material with added glass material to give it better physical properties. Immediately price and delivery time were indicated. At about € 40, it came at 1/5 of the price for the CNC part and was already colored. I could not resist.
The part arrived about a week later. I was impressed with its precision, it fitted first time round. All that was needed was to improve on the design to fit the process of its manufacture.
After a couple of redesigns (you quickly pick up on the general idea), I now have the first concept version prototype of an e-bike product that is well-known by insiders around the world – the Cycle Analyst V3 e-bike computer.
The original Cycle Analyst V3
For the last couple of years, GRIN technologies has been selling the Cycle Analyst V3, an e-bike computer for e-bike enthusiast that has been developed by the Canadian Justin Le.
I was involved in its CE-certification and know the device well, having sold and modified so many of them myself.
The Cycle Analyst V3 comes in either in a DP- (without external speed sensor) or a DPS- (with external speed sensor) version.
GRIN technologies original Cycle Analyst V3, here the CA3-DP version
The Cycle Analyst consists of a circuit board with a LCD display, enclosed with a plastic housing. A number of cables exitting the unit at the bottom, to which a variety of devices can be connected. The unit can be affixed to the e-bikes handlebar with a clamp.
The majority of connectors are terminated with JST-SM type connectors, a TRS communication cable and a DC power jack.
I would guess the Cycle Analyst V3 dust- and waterproof rating is somewhere around IP53 to IP54. The big drawback are the JST-SM connectors, which are not meant to be used outside in an unprotected use, and its housing, that breathes through its cable entry ports and where a thin silicon sealant layer between the housing halves of the Cycle Analyst tries its best to keep the weather away from the electronics.
Re-engineering the Cycle Analyst V3 lower case half, connectors and handlebar clamp
These parts are replaced:
Cycle Analyst V3 original lower housing half with handlebar clamp and cables
Once the clamp and the cables are removed, you can see the bare backshell of the Cycle Analyst V3, below from the outside...
Cycle Analyst V3 rear housing half - outside
...and the inside.
Cycle Analyst V3 rear housing half - inside
The new Cycle Analyst V3 rear housing, connectors and handlebar clamp
I replaced the JST connector system with a HIGO connector system. These connectors were developed especially for e-bikes. They are very compact, and have an IP66 dust- and waterproof rating owing to the molding process where the soldered contacts and the cable are encased with plastic. The HIGO Mini-B Series especially has a soft molded PVC lip that flows over the hard-PVC core of the opposite connector when plugged in, holding the connection firmly together and protecting it, even in a tough outside environment some e-bikes sometimes encounter.
The HIGO-Mini B connectors are also available as panelmount connectors, which make them perfect for the job. Small, space-saving and reasonable priced, they fit the new modular concept that I have been thinking of.
The new CA3 backshell fits the original topshell of the Cycle Analyst V3. Even the screws and O-Rings can be used again. And of course the circuit board with the LCD-display.
Up to 11 HIGO Mini-B Series panelmount connectors can be fitted. A main cable port to the controller/shunt is provided, and a second main cable can be used if needed, provision is made in the backshell for a hole to be drilled in a predefined location.
Just for the fun of it, I decided to order the backshell pigment-dyed in blue.
Cycle Analyst V3 3-D printed rear housing half
As you can see in the picture, a potting pan is provided around the main cables to seal the entry area off with epoxy casting. Also visible are the flattened anti-twist-holes for the HIGO Mini-B connectors. The only requirement is cutting the M6 x 1 thread for the GORE pressure equalising valve into the backshell with a tap.
HIGO Mini-B panelmount connectors fitted, screws inserted and secured with O-Rings
Once the connectors are fitted, a GORE pressure equalising valve is screwed into the backshell. The housing screws are inserted and the O-rings pushed onto their thread to secure them.
HIGO Mini-B connectors, GORE pressure equalising valve, screws and O-Rings fitted to new Cycle Analyst V3 rear housing
To see what the device now looks like, here it is turned face up. Next to it are the 2 handlebar mounting clamps and the fasteners to affix them.
Cycle Analyst V3 Custom with handlebar mounting brackets
Attached to the Cycle Analyst V3 Custom, the handlebar clamps allow a quick mounting/dismounting utilising a detachable clamp half. Clamps are uniside, made from alloy and are anodised black. All fasteners are Torx type and made from stainless steel.
CA3-Custom with 1 1/4“ or 31.8 mm handlebar clamps
Here a picture of a CA3-C with a single main cable fitted, ready to be installed on a e-bike with 1 ¼“ handlebar.
Cycle Analyst V3 Custom with HIGO connectors and handlebar clamps
The first pre-series prototype Cycle Analyst V3 Custom, or CA3-C, will be fitted on my e-fatbike 'Project SandCat', currently being built. Here a trial fit to determine cable lenght before the internal wiring takes place.
CA3-C fitted on my project e-fatbike
Here the Cycle Analyst faces the challange of controlling an all wheel drive, or AWD e-bike. It has to withstand some realworld, extreme testing before releasing the production model of the CA3-C in a small series in 2018.