Printed 3D metal better than a Casting

[Charles LamontParticipant @charleslamont71117]

I recently had some small parts from Craftcloud, printed in Hong Kong. They were modeled in Onshape, .STL files exported and sent to Craftcloud, manufacturer selected, ordered on 20 April, and arrived on 7 May. All the parts were within the weight for minimum manufacturing charge, but even so, having a second one printed added only about 50% to the cost. So that’s six parts delivered for £120.

All the parts are for my Westbury ‘Seagull’ 10cc twin. There is a carburettor body, and the bearing housing and volute casing for a water pump. The carburettor body is designed to look similar to the original, but to incorporate some of Graham Meek’s improvements. The results are generally very good and accurate, though rather generous on size. Holes in particular can be smaller than specified. This does not matter if they are intended to be machined, but one of the advantages of the process is that complex and inaccessible internal shapes can be made. In this case, if I had known about this issue, I would have designed the internal spiral volute on the CAD model oversize to compensate.

So far I have machined one bearing housing. It machines pretty well, without the soft gummy character of some castings and without any tendency to make bird’s nests.

[Neil WyattModerator @neilwyatt]

This is definitely an area that’s going to take off for the hobby in the next few years.

I think it could completely reinvigorate the modelling of unusual prototypes and one offs, as it totally changes the economics of short-run ‘castings’.

Expect to see Julie’s article on the properties of 3D printed steel around ME&W issue 4780.

Charles (and anyone else experimenting with this) I would be very keen to see articles on how you get on with such print and especially to receive some build articles featuring 3D printed parts.

Neil

 

 

[David JuppParticipant @davidjupp51506]

I’m a fan of 3D printed metal parts.

I think it would be helpful if potential articles also included any negative aspects that people might have encountered when working with them.  As with anything new – avoiding pitfalls that others have suffered is key to being successful.

[Neil Wyatt]

On Neil Wyatt Said:

This is definitely an area that’s going to take off for the hobby in the next few years.

 

I think it could completely reinvigorate the modelling of unusual prototypes and one offs, as it totally changes the economics of short-run ‘castings’.

 

Expect to see Julie’s article on the properties of 3D printed steel around ME&W issue 4780.

Charles (and anyone else experimenting with this) I would be very keen to see articles on how you get on with such print and especially to receive some build articles featuring 3D printed parts.

 

Neil

 

 

It is only economic for certain items so at the moment is not a complete game changer but should be treated as just another option.

I had some parts cast at the end of last year, couple of 9″ flywheels and a base for an engine that was approx 100 x 60 x 40 all in grey iron and it cost me around £300.

Cheapest 3D print for two flywheels in stainless to get some weight to them would be £477 the pair and the base in aluminium £123 so certainly not the most economic method. It would actually have been cheapest for me to buy a block and two slices of CI and then cut them on the CNC which would have been about 60% of the casting cost but for various reasons I got them cast.

Or take the Steven’s model that I wrote up last week, 3D printed frame was about £30 but I could have fabricated it for less from a few bits of steel and a couple of inches of silver solder. But having it cast would likely have been in the region of £60-70 as the foundry pricing seems to be Item cost plus material.

From what I see on all the forums and other social media the biggest hurdle for many is producing a suitable CAD file of the required part

Have a look through the stationary engine section of the forum for “Willie” the wobbler, Basset-Lowke Twin (BLT) and Stevens’s Marine Screw Engine if you want to see 3D metal prints put to use

[alecsParticipant @alecs]

<p style=”text-align: left;”>How far away are we from model engineers being able to 3D print aluminium at home, making it more economical?</p>

[JasonBModerator @jasonb]

While you may just get an FDM printer set up for the cost of a new Myford the ones that produce the items shown here by bonding layers of metal powder with a laser are considerably more expensive so really out of hobby reach.

 

FDM – has metal particles and a binder in filament form so prints in a similar way to “plastics” you then melt out the binder and sinter the powder.

 

[alecs]

On alecs Said:

How far away are we from model engineers being able to 3D print aluminium at home, making it more economical?

Never say never, but I suspect 3D printing of metals is a fair way from being affordable in a home environment, and is unlikely to be more economical than outsourcing.

The common method of producing 3D printed metal parts uses high power lasers to selectively sinter, or melt, successive thin layers of finely powdered metal. These types of machines cost from ten of thousands, to hundreds of thousands, of pounds. In addition the printing chamber is flooded with an inert gas (usually argon) which is an ongoing expense.

I would agree with JasonB that the biggest challenge for 3D printing in the home workshop is the unwillingness, or inability, to learn and use 3D CAD.

Julie

Edit: With the metal loaded filaments mentioned by JasonB the sintering/melting stage has to be outsourced.

[BazyleParticipant @bazyle]

At the moment half to 2/3 the cost of a metal print seems to be the shipping and agents’ fees and taxes. Just imagine if you lived in one of the towns in China were these things are currently being printed. You could design something one weekend and have it in your hands the next at less than we pay for the billet to machine it from solid.

Maybe we will get to a stage where larger towns in the UK do have a print shop like they used to each have a foundry.

[JasonBModerator @jasonb]

But would they be cheaper, I doubt it.

Craftcloud gives me many quotes, the most expensive are from Europe yet they have the least distance to travel. Tax (VAT collected at source) is included in all those prices. Highest not shown is Portugal at £344

Also quicker from China than Europe

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