3D Patterns for a Threshing Drum

I was over on Traction Talk Forum yesterday and Ian (Shiremog) had posted a photo of some 3D printed patterns for a 3" threshing drum he is making, he has said its OK to share the photos here which I thought may be of interest as its always better to see the prints being put to a use we can relate to rather than printing out trinkets etc. The printer is an Ultimaker2, the same as Andrew J uses.

Some of the patterns, apparently there are over 120 castings in the model all home cast in aluminium or bronze. Click for a larger image

More detailed shots of some of the patterns, the small cube is a core box - its an easy job to click a button and print the space around an object rather than the object itself.

And a pic of the wheel hub with the holes for the spokes to fit into, wheel is 10" dia for an idea of scale.

Edited By JasonB on 03/06/2015 10:04:06

One and a half to two grand for a unit and you're good to go

This could really give the castings market a boost, all sorts of projects become possible

How much is the raw material for printing?

Looked it up, about 30quid per 0.75kg, so not cheep for the good stuff, say about 5kg for that set of castings, 150 to 200 quid?

Edited By Ady1 on 03/06/2015 10:59:20

Sorry Jason couldn't resist putting up these couple of photos of my Grandad with the real thing...

No probs if you want to delete of course!

Cheers

Garry

Cheers

Garry

Pneumatics !! That's posh

Yes we set the trend down here for others to follow Diane..!

Very impressive. There will be some tricky sand moulding ahead. I look forward to seeing the castings.

Thanks for the heads-up Jason.

Rod

Great prints too.

Will he being doing 'lost PLA' or making conventional moulds (as hinted by the use of a core box), or a mixture of both?

Neil

Neil, if you take a closer look at the patterns you will notice a white dusty look to them where they still have talc on the surface used as a release agent to stop the sand sticking. Traditional sand casting with single or two part patterns as needed.

Rod a few of the finished castings can be seen in teh last photo I posted.

Couple more, this feed screw would have been impossible to pull from a two part mould so it was screwed out of the sand to leave the cavity, hence its not as good a finish as the other castings.

.

Jason

Think you have the last mixture mixed up unless they are casting in wood ?

Big dusty machines, remember working on one in the 1940s bagging the grain.

Another one that needs to go to spec savers, look closely and fixed to the wood are various bits of metal, just above the wheel is the bronze casting of the curved spoke pully the pattern for which is in an earlier photo, several other bits in bronze & ali there too.

> talc on the surface used as a release agent

Ah, I assumed is was some sort of bloom, probably because I saw a particularly faded red car yesterday.

Neil

This fellow is very skilled looking at the patterns. Was this his profession?

Brian

The skill here Brian is drawing in 3D, the printing is virtually automatic.

I would have thought the skill is in the use of scissors to cut the 3D print to the proper shape. Or did he use origami?

You still need to know a bit about pattern making, easy enough to draw up a part but not much use if it can't be pulled from the sand so correct draft and maybe loose piece need to be added or you don't add machining allowances where needed. Also think about how you will machine the part - a simple chucking spigot added at the time can make life a lot easier. If using iron thin extremities can get chilled so again its worth adding a bit of extra material to the end so that can be cut off to leave good iron where you need it.

J

Could the patterns be made available for sale/loan/hire as I am in the early stages of building one of these machines?

Keith, your best bet would be to join Traction Talk forum, only needs an e-mail and then you will be able to view this thread and ask Shiremog himself.

J