AM3300 ColorFabb nGen filament

I have just done my first print with ColorFabb nGen filament.
The results are excellent.

Slightly slower to print with than PLA, I used the recommended 50mm/s for the nGen where I can reliably use 60mm/s with PLA. However, both are much faster than the 30mm/s I have to print with PETG.

I'm using nGen because I want the higher temperature tolerance, so I can use the finished article in a car. I normally use PETG for in car use but, as I've said, that is slow and troublesome.

I did not have any issues with a 25 hour print using nGen. It stuck to the bed without warping and negligible stringing and blobs. Both significant issues with PETG.

nGen is ColorFabb's brand name for "Eastman Amphora™ AM3300 3D polymer" filament.

If it survives the summer temperatures in the car, I think this will be my go to filament for things that need that little extra strength or temperature resistance.

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Update 25 June 2020

Over the last week or so, I have done a lot of prints using nGen filament. These range from 3 hour to 25 hour prints. I have not had a single failure. Everything sticks to the glass bed, without any assistance. Good layer adhesion. No warping or noticeable shrinkage.
I've had a couple of the prints in a car for a few hot days and no sign of any distortion.

Just based on my feel, I would say that nGen has about the same layer adhesion as PLA but is overall stronger. With the grain, nGen can take quite a lot of flexing, much more than PLA.

The surface finish is good. It gets the odd tiny bobble, which I can usually scrape off with my fingernail. It can have a tiny bit of very fine stringing but that depends on the model being printed, some have none. Again, easy to clean up. I can rub it off between my fingers.

I plan to buy nGen filament as my primary material to print with, from now on.
I have lots of PLA left in stock and a little PETG. I will use that up over time but I'm unlikely to keep much of either going forward.

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nGen, AM3300, Setting:

Nozzle temperature = 235C

Print speed = 50mm/s

Travel speed = 100mm/s

Cooling = 50%

Bed temperature = 85C

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Compare Filaments

I have found it difficult to get reliable information about filaments.

The information I am particularly interested in is at what temperature does the material deform. More specifically, will it survive the temperatures inside a car during the summer.

The most appropriate measurement I can find for that is:

Heat Deflection Temperature (HDT). It is when the shape will start to change due to the heat under a given pressure. This is typically quoted at one of two pressures. Either 0.46MPa (66psi) or 1.8MPa (264psi) or both.

That is not the Glass Transition Temperature (GTT), which is always higher.

The following are my own conclusions from various sources.

Generic PLA

Material: Polylactic Acid (PLA)

HDT = 49C to 52C at 0.46MPa 

Reliable print speed: 60mm/s

Comment: Easy to print with.

ColorFabb nGen

Material: Eastman Amphora™ AM3300

HDT = 71C at 0.46MPa and 63C at 1.8MPa

Reliable print speed: 50mm/s

Comment: Easy to print with. Stronger than PLA but not as strong as PETG or ABS.

ColorFabb XT

Material: Eastman Amphora™ AM1800

HDT = 70C at 0.46MPa and 62C at 1.8MPa

Suggested print speed (mid range): 40mm/s

Comment: I have not tried this. Apparently, another one that is more difficult to print with.

ColorFabb HT

Material: Eastman Amphora™ HT5300

HDT = 

Suggested print speed (mid range): 40mm/s

Comment: I have not tried this. Although tough it is apparently more difficult to print with.

Generic PETG

Material: Polyethylene Terephthalate Glycol (PETG)

HDT = 63C at 1.8Mpa

Reliable print speed: 30mm/s

Comment: Difficult to print with. Strings and blobs easily form and the nozzle gets covered in filament, requiring cleaning.

Generic ABS

Material: Acrylonitrile Butadiene Styrene (ABS)

HDT = 88C to 100C (1.8MPa)

Suggested print speed (mid range): 60mm/s

Comment: I have not used this due to the well documented fumes. I am confident they will, at the very least, irritate me but more likely, cause me harm.

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Sources:

https://www.creativemechanisms.com/blog/learn-about-polylactic-acid-pla-prototypes

https://learn.colorfabb.com/print-_xt/

https://www.creat3d.shop/news/creat3d-3d-printing-tips-printing-with-colorfabb-filament.html

https://omnexus.specialchem.com/polymer-properties/properties/hdt-1-8-mpa-264-psi

https://www.lulzbot.com/sites/default/files/AmphoraAM3300-TDS.pdf

http://www.kul3d.com/optimum-settings-for-printing-pla-abs-and-ninjaflex-3d-filaments/

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Bike forks service tool

A friend of mine asked if I could 3D print a 24mm socket for his Rockshox forks.

He's been adjusting the air spring behaviour by adding or removing tokens. The regular removal of the air side insert was leaving signs on the anodising. A plastic socket would be less likely to leave a mark and the air side insert is not done up very tight.

Dean sent me a sketch which included some useful features:

• 19mm hex at the top for a spanner (A 19mm spanner is the largest in a normal set of tools)
• 8mm hex hole for an Allen key.

It took three prototypes to get a version that printed out neatly and could be easily cleaned up. The main design change was to add a slope at the bottom of the 8mm hex tube so, when printed upside down, that tube did not have supports inside that are tricky to clear out cleanly.

In the process I discovered that Fox use 26mm nuts and Suntour use 27mm, in addition to the 24mm used by Rockshox.

I made a set of three, each with the size printed on them.

The 19mm hex is oversize to be tight in a 19mm spanner. The 8mm is oversize to allow for 3D printed shrinkage and was trial and error to get a tight fit.

We don't know how long they will last. I've printed them in PETG being the strongest plastic I have been able to print with.

PETG is a bit finicky to print with. The slower the better. These are the settings I used this time:

Temperature = 240C

Bed temp = 80C

Infill = 100% (Solid)

Print speed = 30mm/s

Support speed 14mm/s

Travel speed = 90mm/s

Cooling = No fans

Supports = only from the print bed

Adhesion = 8mm brim

These settings are for use with an Ultimaker 2+ printed on to the glass without any adhesion aid.

Each took about 4 hours to print.

PETG tends to stick to the nozzle and sometimes this forms lumps and messes up the layers. If this happens somewhere significant I tend to abort the print and start again.

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Fruit cage

A few hours on a warm Sunday.

I started with only a vague plan and 20 lengths of timber. 2.1m x 50mm x 25mm.

The side netting is held on by cable ties and the roof is pulled taught with plastic 'S' hooks.

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Merida One-Twenty 7.800 suspension bearings

I hunted all over the internet to find out the sizes of the pivot bearings in the frame on Shelley's bike. I did not have any luck finding any details for the 2015 model year.

The only solution was to take the bike apart and measure them.

Although I double checked and took measurements, if you look very closely at the seals, they include a part number.

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Download the diagrams as a PDF.

Updated: 23 May 2021

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Handlebar stabiliser

I've been looking for an easy to use handlebar stabiliser for use with the bike repair stand.

The one that looked like it would do the job is the Park Tools HBH-2. Unfortunately, in use with mountain bikes, it has a tendency to allow the bars to move too easily.

I used some elasticated shoe laces to make a small improvement.

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Bike maintenance experience

You can watch all the YouTube videos and follow all the instructions to the letter but sometimes you only get it right with experience.

My bike has been rattling for a week or so and finally I found the issue.

The cassette was loose.

When I changed the rear wheel, I had set it up exactly as per the original. What I now know is that there are sufficient differences between freehub drivers that some of them need spacers.

I've stripped it down, cleaned it up and fitted a 1mm spacer.

That's enough to allow the lock ring to clamp down on the cassette rather than on to the end of the freehub driver!

That's done the trick and the cassette is secure. I've adjusted up the gear change and taken it for a short test ride.

I also had a creaky bottom bracket (BB). Apparently this is not uncommon and not always easy to fix.

My attempt, at a fix, is to take the cranks off, put the BB press back on and clamp it tighter. I then re-assemble it.

The short test ride tonight is not sufficient to know if the creak is still there or not.

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Update:
I've been for several rides. The creak was gone initially but returned on the third ride as noisy as ever.

"I wonder if anyone will ever do do a SRAM dub compatible press fit bottom bracket with a threaded inner sleeve to lock it in place?"
Perhaps I need to work on that design.

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Wash your hands and stay safe

During these times of social isolation, due to Covid-19, Shelley is continuing to garden, as long as it is safe to do so.

Staying away from people, in her job, is not difficult however, she may not always know what her customers have touched in their gardens. She needed to be able to wash her hands. To that end, her Defender now has a hand gel dispenser.

I designed and 3D printed a simple holder that easily hooks on the dash.

Printed in two halves to avoid the need for masses of supports.

It has a simple joint formed of an arc, 10mm wide by 1mm deep.

It slides together like a dovetail joint but does not have an overhang so it can be easily 3D printed without supports.

It's printed in PLA, for ease and speed, so it won't survive hot sun in the car for a prolonged period. Hopefully we won't be in 'lockdown' for so long that it matters.

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