How to print 180 mm H beam  

RE: How to print 180 mm H beam

on end?

RE: How to print 180 mm H beam

On end would not require supports, bit would be very prone to breaking along layer lines.

Will this be a load-bearing part or only decorative?

Is it a part you've designed? If you can use chamfers instead of 90 degree angles, you might get away without supports printing horizontally.

RE: How to print 180 mm H beam

The photo is just a rough example, the part I need to print is more complex (with some nerves on the inner sides). The part is for a prototype that would have to bear some weight, thats why I am unsure about printing it on end. How easily would it break? The walls are around 2-3 mm thick.

Thanks 

RE: How to print 180 mm H beam

Strength will depend on what filament you print with, but FFF printed parts will be weakest along layer lines. 

Can you zip and upload a 3MF project file of an example? It's hard to offer up much more otherwise.

RE: How to print 180 mm H beam

Thanks for your help!

Unfortunately I can't upload the file as its for work (so its confidencial). 

I will just have to print it on end and see if it is strong enough. Otherwise we are thinking of trying filament with carbon fibre. 

RE: How to print 180 mm H beam

Hi Emily, 
can you tilt the  girder 45 degrees, add sacrificial gussets and print like that?

if you want strength, use the largest layer height that provides an acceptable finish, 
add enough perimeters to completely fill the model without infill. 

use a slightly higher extruder temperature than normal for improved inter layer bonding,

try 65 or 70C for bed temperature and 

use a brim of say 10mm  both of these will promote adhesion

as modelled, the gussets have the contact edge chamfered to create a break point when the model is finished, to ease removal

In this orientation, the centre web of the girder will be stronger than it would have been if it were vertical,

the top and bottom elements of the girder will probably have similar longtitudinal strength to a girder printed with the web vertical but the lateral strength of the top and bottom  elements is likely to be marginally lower, however this factor is probably irrelevant in an 'I' beam girder solution

regards Joan

RE: How to print 180 mm H beam

From a engineer point of view...

If your design and application allows print end down/up and add "channels/holes" that go through the Z axis that will allow you to run metal rods through for strength.

RE: How to print 180 mm H beam

With a wall thickness of 2-3 mm, that does not leave much room for metal rods.

I do like Joan's design a lot. Clever way to avoid supports - and a lot stronger than printing on end.

RE: How to print 180 mm H beam

I missed the 2-3mm thickness, not that thick. I'm missing something with Joan's design, how is the the far left printed with no supports?

RE: How to print 180 mm H beam

Grumble. I missed the far left. Makes us even! Support is required on that edge.

RE: How to print 180 mm H beam

I'd try for laying the thing over on a side, with a custom support mid-beam to help with bridging anomalies.

ps: In truth, it might print well enough with no supports, but tension of the unsupported bridging may bend the two rails inward.

RE: How to print 180 mm H beam

@gkmakeit

Oooops... yeah! brain fart...

Joan

RE: How to print 180 mm H beam

You've not the only one, my brain does the same thing sometimes!

I was really hoping I was missing something, new feature. 😀 

RE: How to print 180 mm H beam

better?

Joan

RE: How to print 180 mm H beam

Makes me happy anyway!

RE: How to print 180 mm H beam

Thanks for all of your help! To create the personalised supports what program do you use? I have just started using Prusa Slicer but I feel like there isn't an option for customization. 

If you model the supports in CAD before importing into a slicing program, what support thickness would you recommend? And what distance should I leave between the supports and the part, for easy removal?

RE: How to print 180 mm H beam

Sometimes trying to recreate a design suited for another material is not the best solution for FDM printing.

Whilst an I beam is a much superior solution for supporting a weight compared to the same amount of steel but made as a solid bar, this design does not necessarily translate as suitable for other materials.

In FDM printing, we can create filled parts like a square section beams but with a gyroid infill, you could not do this unless you print it layer by layer, but it does result in a much stronger part that is relatively easy for a 3d printer to produce.

Does your design have to use an I beam or are you thinking that since this is used for supporting loads in construction, then it must also be suitable for 3D load bearing, if it is purely decorative, then Tim's approach is probably best for strength, but can be beset with distortion due to the bridging filament contracting as it cools, pulling in already laid bridges below and causing them to sag, the centre support will probably eliminate most or even all of the sagging though, but you could still end up with a slight step at the centre bridged section.

RE: How to print 180 mm H beam

@emily

Hi Emily, 

I modelled the supports in my 3D design progam, before importing to prusa slicer, 

for the triangular supports I used 1mm thick and put a o.3mm chamfer on either side of the contact patch simply for demonstration purposes. 

the thickness of the braces is a trade off between increased print time and excess waste, to greater rigidity and greater adhesion

I have printed a tall thin  vertical object with just a single brace that only contacted the  the part that it was bracing four times, up the height 
I estimated that this would give adequate support as the model progressed and I was lucky to get success, you have to be prepared to experiment... 

your biggest problem is going to be adhesion to the heatbed, which is why I added the brim, to increase surface area on the heatbed. 

the number of triangular braces is a total guess as when I created the example I had no idea what your overall dimensions were...

the braces are there to reduce the liklihood of the part moving during printing.   (Without overhangs (Which I completely overlooked on the top  of the girder first time round. ) a part should be able to print at 45degrees without support) but the problem in this instance is that the corner of the girder would not give adequate contact area...      

If your design would permit the corner to be 45 degrees  for a small contact patch, then adhesion would be improved,  another option would be to create an additional support, a minimum 0.42mm wide by the length of the girder and perhaps 1mm tall, and merge that between the build plate and the corner of the girder nearest the build plate, to increase the contact area at that point to a minimum of one extrusion width with a o.4mm nozzle
remember that if a section of the model gets  smaller than the extrusion width, or smaller than the layer height at that point in the model, the slicer will ignore it's presence...  (Prusa Slicer, with 0.4mm nozzle, defaults to 0.42mm extrusion width for the first layer, and 0.45mm extrusion width for most other sections, with 0.4mm extrusion width for the top layer)

regards Joan

RE: How to print 180 mm H beam

Posted by: @emily

To create the personalised supports what program do you use? I have just started using Prusa Slicer but I feel like there isn't an option for customization. 

 

Hello,

to add supports just where you need in PrusaSlicer, this video will be more explicit than my explanations 😀