Good recommendations for mechanical parts with strength

[Wardad5]

Hello all,

I have a friend designing a bike saddle and he is wanting me to 3D print his prototype. I am wanting to see what filaments would work well for high strength? He wants to be able to sit on it and see how it feels. I am worried that ABS will not cut it. I have a Voron 2.4 so looking to print it on that. As a follow-up question, I have the Phaetus HF hotend and am wondering with whatever filament is recommended if I need a better nozzle (mine is stock) and if so, what nozzle type does this hotend use? I have looked all over online and cannot seem to find a clear answer. Thank you all in advance. 

[smirk]

The Phaetus dragon is compatible with (E3D) V6 Nozzles.If the chosen filament is something with additivies (Carbon Fibre or Glass Fibre) then you'll need a hardened nozzle at the least (like this one)....and at a minimum 0.4mm but perhaps larger like 0.6 to prevent clogging and aide with print speed.

As to filament, perhaps some sort of reinforced filament like ABS+CF, but that's harder to recommend.Depends on the design of the seat and your friends expectation for the testing (whether they're going to gently sit on it for shape/fit/relative comfort; or want to fit it to the bike and have a good bounce on it). I'm not a cyclist but a lot of the saddles I've seen are not simply hard plastic (migtht be a hard sub-shell covered in some form of padding) so I imagine there's a fair bit to select/choose for comfort and fit. It might be a matter of expectation setting rather than filament selection.  If you were designing a part purely to be 3D-printed (on your Voron) then that would involve very different design decisions from something that was a prototype to give someone an idea of "what it looks like" before being manufactured by some more appropriate mechanism (SLS, say)

To be honest there would be nothing wrong with printing it in PLA (or ABS ) for your "this is what it looks like" prototype and if it looks/feels good then follow that wiith something produced in a reinforced filament for a bit more functional testing.However, I think you need to ascertain the "testing parameters" as it were. I don't think a saddle printed (on a Voron) in any filament will be particularly robust if it's been designed like a saddle that will be produced by other means....(if you follow what I mean)

 

[claudermilk]

I am a cyclist, and your guess is pretty good @smirk. A hard(ish) base usually of plastic or similar with some padding. Counter-intuitively less padding can be better than more. There is a ton involved in picking a comfortable saddle--swapping from the stock one to the next wider similar model made a huge difference with my bike.

Anyway, with limited experience in materials I would think for a "here's what it looks like" print anything would do--PLA probably the easiest. For a possible test fit I'd think ABS should be fine. Picking the print settings is important. For this I'd start with Voron specs (4 walls, 40% infill), maybe more walls for additional strength.

I suspect printing a saddle shell on a FDM printer is going to be...challenging. Lots of supports most likely.

[Maurici]

On 2/28/2023 at 11:18 PM, Wardad5 said:

Hello all,

I have a friend designing a bike saddle and he is wanting me to 3D print his prototype. I am wanting to see what filaments would work well for high strength? He wants to be able to sit on it and see how it feels. I am worried that ABS will not cut it. I have a Voron 2.4 so looking to print it on that. As a follow-up question, I have the Phaetus HF hotend and am wondering with whatever filament is recommended if I need a better nozzle (mine is stock) and if so, what nozzle type does this hotend use? I have looked all over online and cannot seem to find a clear answer. Thank you all in advance. 

was this ever sorted?

I can offer a few meters of PC10 from stratasys free of charge... if you are uk based... you won´t do better than this.

I do print that stuff witht the exact same hot end as you do. 335degrees nozzle temperature and no cooling at all with a very well soaked chamber and ST nozzle... Is that good that probably would even do as the real thing, not only as a proto, but either way.

Is a genuine offer and to anybody else too (within reason). I do have around 2.5kg of that stuff and I won´t ever use it all before it goes bad.

It tends to wrap, but as I assume for your application you are only bothered about the upper side, it can be easily printed over a 10 layers raft in a lightly Elmers glue covered smooth PEI sheet. (in fact, even stratasys prints by defect over a 10 layer raft for big parts).

You are likely to ruin the smooth part of your PA sheet, however, in all honesty, I´m sure your mate will be happy to replace it!

Edited March 20, 2023 by Maurici

[Wardad5]

I think I am going to go with some ABS or ASA with multiple perimeters. The offer for the filament is nice but sadly I am in the USA. Thank you for the insights and advice.

[Penatr8tor]

On 3/22/2023 at 9:45 AM, Wardad5 said:

I think I am going to go with some ABS or ASA with multiple perimeters. The offer for the filament is nice but sadly I am in the USA. Thank you for the insights and advice.

If you do... I've had very good results with Polymaker and Prusament both of which can be acquired on Amazon. I currently print with ASA as ABS doesn't offer any properties better than what ASA offers, so why bother with ABS. I mean if there's some color you can't get in ASA.

[Chuck_Snow]

@Penatr8tor I'm having trouble whit getting Polymaker to stick, and it warps a lot for me... Polylite ABS HE255'c Bed100'c on PEI sheet I tried Hair Spray but it doesn't seam to help seam to makes it worst and I find I have to Squish a lot to get it to stick but It still getting corner lifting and warping.

Got any advice ?..

[Penatr8tor]

Hey @Chuck_Snow, I don't print ABS anymore and haven't in a while but... I do print with ASA quite a bit. So here's a few things that work for me printing ASA, it's close enough to ABS that the settings will translate over.

1. Make sure your PEI sheet is clean and oil free. Even a finger print will cause parts to peel. My technique is 70% or better alcohol wipe before every print. If parts don't stick... Fill a spray bottle with water and add a drop of Dawn dish soap. Spray the PEI sheet and wipe with paper towel. Then alcohol wipe. If things still don't stick... wipe the PEI sheet with acetone. Don't wipe over any screen printed Voron logos or text as it will dissolve/smear them. I only use acetone maybe once a month if I'm doing a lot of printing. Once in a while is OK, it etches the surface a bit and gives the surface a little extra tooth to promote adhesion. I never use glue stick but do have a can of Aquanet on hand just in case. 

2. Print settings: My HE is 250c, Bed is 110c That should be good for ABS. 255 at the nozzle is also good but I would 100% up the bed temp to 110c. I found that a 0.2mm 1st layer sticks better than 0.3mm, I also print my 1st layer at 30mm/s. Any faster and I get peeling. I was running my part cooling fan at 40% after the 3rd layer. I was having a lot of problems with peeling even though my chamber temp was around 45c, you want your chamber to be around 38c min BTW. So anyways... After trying a bunch of stuff I decided to reduce the PC fan to 30% and have it come on after layer 5. That helped a lot. I can't say you'll never have a sticking problem, but you will greatly reduce failed prints.

Lastly... I can't stress enough about being OCD about keeping you PEI sheet oil free.

Cheers! Report back, let me know what worked for ya.

[mvdveer]

On 4/29/2023 at 1:42 AM, Chuck_Snow said:

@Penatr8tor I'm having trouble whit getting Polymaker to stick, and it warps a lot for me... Polylite ABS HE255'c Bed100'c on PEI sheet I tried Hair Spray but it doesn't seam to help seam to makes it worst and I find I have to Squish a lot to get it to stick but It still getting corner lifting and warping.

Got any advice ?..

It is a good idea to prepare the PEI plate before printing by washing it in hot soapy water and scuffing it with 1500 gram sandpaper.

Then follow @Penatr8tor advice to get consistent adhesion.

I tend not to use acetone but rather scrub the plate with a dishwasher pad in hot soapy water once a month, depending on the amount of printing I do. Printing with eSun ABS+ and have very few adhesion issues.

[Penatr8tor]

5 hours ago, mvdveer said:

I tend not to use acetone but rather scrub the plate with a dishwasher pad in hot soapy water once a month, depending on the amount of printing I do. 

I'm going to have to try that method. I'm hoping I don't have to use acetone unless I'm in a real pinch.

[Chuck_Snow]

I have printed over 400 hours of abs+ and some other, I just got a few Different brands to try and PolyLite ABS seams to warp no matter what I do,, even whit 40+c Chamber..  and my fan are only 20% 25%on over hangs ..

ect.. I'm trying to print my Mercury one parts, and well I have it now I like to used it up..
Maybe scrap that idea and just go back to E-Sun or print them in ASA Sparta3d .. 

And ya it is a new build, I was going to sand/Scuff my plate..

Edited April 30, 2023 by Chuck_Snow

[ken226]

Some shapes/designs are very susceptible to warping, others not so much.

 

In addition to the advice above, to help with adhesion, you can dissolve about 6 inches of abs filament in a couple ounces of acetone to make a slurry.  Brush a small amount of the slurry onto the print area of your build plate.   also, I like to use a connected brim around the first layer of the part, to help keep the corners from lifting.

 

As for the design, when printing with ABS, if there is a large footprint,  it's helpful to  avoid long, strait extrude lines.  Various holes, shapes or angles can be used to break up long, strait extrudes. 

 

Here is an example.  This part, was very hard to keep from warping.  Both of the corners on the left end would start to lift every single time.  Even with a brim, slurry, spotlessly cleaned PEI bed.  

 

Adding some cross holes to break up the long, linear extrudes in the long sides of the walls, cured the issue.  This version prints with no trouble:

 

 

 

Another example.  This 14 inch long neopixel bar with an integral Logitech C270 mount warped like crazy.  Both ends would pull up, every single time.

 

But, a couple of V notches to break the long extrudes into shorter sections, and It was much easier to print.  Also, rotated so that it prints with the middle recess oriented up, helps shorten the extrude lengths:

 

 

Edited May 28, 2023 by ken226

[claudermilk]

Brim ears might help with the warping, it has for me.

[G_T]

I'm new here but will throw in my 0.02c. I've put in over 30K miles on road bikes and spent a lifetime making stuff of all sorts, so...

A bicycle saddle can be inadvertently subject to momentary high force. A bicycle saddle is going to be subject to UV. A bicycle saddle is going to be subject to water - rain or sweat. Dirt. Oil picked up from the road. Etc.

A biycle saddle that fails on a ride is a major safety concern. I was 3rd in a line and the leader jumped a substantial pothole but didn't flag it. The 2nd guy got his weight off his saddle. I didn't have time. I hammered my seatpost down on the frame and broke the saddle. Also hurt my hip. I had 10 miles of hills left to peddle, standing, with an injured hip. I couldn't get back to normal riding for a year.

Now if that had been a carbon fiber reinforced saddle of some of the plastics being discussed, I'd have also had carbon fiber bits of plastic stuck in my butt. Given there are serious blood vessels nearby, that could have been fatal.

For this application, for anything that might actually be ridden, or even IMHO sat on, you need something that will flex a long way, and tear with great resistance rather than fail catastrophically. Somebody being injured on your prototype would be your problem as well as theirs. I'd be looking at the nylons for instance, and possibly others. And I probably wouldn't be looking at FDM printing.

Gerald