Using 3D prints for casting

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Neil Wyatt on 22/02/2015 10:23:05:

> I wonder if Neil conducted his recent survey with that possibility in mind.

No…

.

Neil,

Just to confirm .. There was nothing accusatory in my 'wondering'.

It could, I think, be a logical extension to the Plans Service [provided that you could get the DRM sorted to everyone's satisfaction].

MichaelG.

[Peter BondParticipant @peterbond14804]

Posted by Neil Wyatt on 22/02/2015 10:23:05:

The crude drawing was to help me figure out what a link looked like from photos of the outside of the track, the lower drawing is obviously from a contemporary manual.

You are aware there's an example at Bovington?

http://www.tankmuseum.org/museum-online/vehicles/object-e1952-30

Edited By Peter Bond on 22/02/2015 13:57:26

[Neil WyattModerator @neilwyatt]

Thanks Peter

yes, I have lots of pic of the Bovigton example.

Neil

[John Stevenson 1Participant @johnstevenson1]

Couple of weeks ago clumsy Son in Law kicked the door off the washing machine, simple accident but he's still a clumsy f@#~>.

Quick strip down and turns out to be a couple of simple hinges with a bit of needed detail and also some not needed to save material on the original moulding.

So quick visit to Thingiverse.com so she if there are any free files there. Quite a few but none for this model.

At the moment I still suffer from not getting started on 3D CAD because if I was able to draw this I could make it, and after I have drawn it I could also upload it to thingiverse so someone else in the same boat.

As it was, because the washer was needed, had to nip out into the workshop and make two up in brass as I know that technology.

The other hinge was non existant.

Something I'd like to mention as it has been brought up before but with this Makers hobby there are two sides to it.

The side where they make everything and give all the designs and software away and the buy already done like the UP printers.

The later falls into the category of what I prefer to call Cheque Book Engineering where you know what you want, want it now and need it to work. Andrew is a very good example of this.

The first part is why Thingiverse exists and the open source software to run the home made machines.

However because of these two extremes, free or nearly so and commercial units with sales aimed at small industry or really serious hobby there will never be a middle ground.

It simply can't exist as there is no profit margin between free and an already saturated commercial market.

So will we see the likes of Warco / Chester / Chronos /ARC / Amadeal selling these ? My take is no because you can't make money at it which is what these people do and they will leave it to the likes of Mapin / RS and the dedicated manufacturers and concentrate on markets they do know.

[Andrew EntwistleParticipant @andrewentwistle]

My 3D printer actually falls more into the home made category. I made the extruder from scratch and used it to optionally replace the woodworking router / outrunner spindle on my ex-education CNC machine running under Mach3. Total cost for the 3D printer option – stepper motor, driver, heaters, controllers and bed etc. was no more than £100. After a couple of months I have still not made anything genuinely useful that I could not have made by turning and milling. it is very satisfying though to make a 3D design one evening, then during the following day it is manufactured (less fettling) whilst I am at work.

[Anonymous]

Posted by John Stevenson on 22/02/2015 16:32:06:

The later falls into the category of what I prefer to call Cheque Book Engineering where you know what you want, want it now and need it to work. Andrew is a very good example of this.

Darn it, my cheque book is under the misaprehension it has been insulted, and has spent all day sulking in the corner as a result.

Andrew

[Four stroke FredParticipant @fourstrokefred]

Having just acquired a 3D printer thie last 7 days has been a big learning curve but also great fun. I am looking forward to developing the prints as patterns and core boxes for sand casting. The photo shows my efforts with parts for an IC engine ( a flat six) . The engine was a "theory" design and was never made but it's good to see it in 3D.

George.

[AjohnwParticipant @ajohnw51620]

My interest in casting has led to an interest in using 3D printing to make patterns for sand casting. There are some caveats. The machine at the price I am likely to spend will probably break from time to time and will also probably need some sensible modifications. Going on results produced by various people there is clearly a learning curve as well especially related to machine settings.

3D printing can be used to make all sorts of things. It's another area where just like a lathe it fits in with an interest in astronomy. That's just a for instance. I'm also interested in model aircraft and helicopters at times. From my product design days I know that ABS is one of the more interesting plastics but it seems nylon and polycarbonates are also possible but have their own problems.

The main problem with 3D printing really is that it's incredibly slow otherwise it would probably be used to make all sorts of things. As it is it's basically most suitable for prototyping.

Looking at previous posts – pay some one to do it. I suspect that would be a none starter compared with owning one of the cheaper one such as rep rap etc. The process also has some limitations on what can be printed but things like twin extruder printers are available – I wonder if they are any good. I suspect I may be finding out at some point but gluing 2 parts together is probably a more sensible approach.

John

–

[EnnechParticipant @ennech]

I often stick parts together, its a benefit of using ABS. Just coat the two parts with acetone and hold together for a few seconds. They stick like the proverbial!

[AjohnwParticipant @ajohnw51620]

Gluing sounds preferable to risking a twin extruder putting down soluble and then accurately putting something else on top.

ABS has some bad press now – nano particles, all over the web. That sounds more worrying than what it really produces – smoke. Clearly breathing in smoke is best avoided what ever it's from.

John

–

[MuzzerParticipant @muzzer]

There are many companies providing 3D printing services. You upload the file, they print and send it to you. Never used them myself but if you want to avoid the expense of buying a printer and messing with it for weeks, this may be an attractive option.

There are now some affordable SLS printers about now apparently. Some interesting resins available for them too, including "castable" and "tough" versions. The former suitable for investment casting and the latter having decent strength.

As you say, John, there's no such thing as safe smoke.

[AjohnwParticipant @ajohnw51620]

The resin printers tend to be much smaller and don't show any signs of dropping to the price of the printers. Resins can be expensive too.

Just look at what can be printed in one go

Joking aside the shot does show that there is some sense in them. They can or / do use bearings and loads are low. Thy don't need anything like the degree of rigidity cnc machines need. One criticism I have heard is that running the stepping motor around along with the extruder spoils things. It seems some may have messed around with running the filament through a bowden cable.

John

–

[MuzzerParticipant @muzzer]

Well, you've got to either mount the feed motor on the head so that it has to be driven back and forth (not ideal) or use a remote feed motor and Bowden cable arrangement. IIRC, most seem to have taken the latter route and work well.

[Andy from WorkshopshedParticipant @andyfromworkshopshed]

I've recently cast a flywheel using a 3d printed two part pattern. Here's the details of the pattern, how it was used and a bit about melting the metal. Start to end for the casting process was about 4 hours but I did make some ingots too.

Workshopshed – Printed Pattern

Workshopshed – Setting the pattern in the sand

Workshopshed – Melting and pouring metal

I've learnt most of what I know from reading the Dave Gingery book of the charcoal furnace and also also Lionel Oliver II's book of the flowerpot furnace.

Since having the pattern for this printed I've gained a Robox printer so the next pattern for my project will be printed out with that.

Edited By Andy from Workshopshed on 07/04/2016 10:32:19

[AjohnwParticipant @ajohnw51620]

Posted by Muzzer on 06/02/2016 16:45:25:

Well, you've got to either mount the feed motor on the head so that it has to be driven back and forth (not ideal) or use a remote feed motor and Bowden cable arrangement. IIRC, most seem to have taken the latter route and work well.

I've heard from people that use them that there are swings and roundabouts. The software can pull the filament back when moves are made. The bowden arrangement can be problematic in that respect. Also comments that 3mm filament is better than 1.75 on this type. 1.75mm will it seems feed more quickly with less drive power so may allow faster prints.

As it looks like I will be building the lot myself I intend to use nam23's on x and y. It seems that the hot ends can be directly mounted on the boden feed unit's so the same kit can be used for both. That's according to a book but I have taps etc so should be able to make it so if needed. Z not sure yet but if the table lifts a nema 23. If off my own bat I decide on something like a router set up nema 17's.

John

–

[ZebethyalParticipant @zebethyal]

Many ways to skin a cat, as have already been mentioned, and all have their place, but quite often just because you can use a particular approach does not make it the best or most cost effective.

I could have made the plastic parts for my Buildlog laser cutter by milling them from Acrylic or HDPE or laser cut them from acrylic, but chose to 3D print them, time taken to produce them was much higher, but the material cost dropped from £20+ to pennies, plus I did not need to babysit the printer. The other manufacturing options were all available to me, just as viable for making the parts in question, and would have taken less time but I chose to base my choice on raw material cost.

3D printing for investment casting or mold making are both viable options.

I believe 3D investment printing makes more sense for smaller detailed items where the time taken and filament required to print is low – a friend of mine has had great success with his cuff-link designs, sending them to Shapeways, he uses the various plastic options for proofs of concept and fine tuning the design, then various metals via lost wax investment casting for the finished items, all at reasonable costs (small items).

For larger items, like say a flywheel other methods may make more sense, your more typical wooden mold, or possibly a polystyrene foam investment option.

Building a polystyrene foam investment from regular shapes and gluing them together (mikesworkshop), mill them from foam or use a CNC hot wire cutter for more complex shapes again with the option of gluing on sprues, etc, all with a cost of pennies for the foam even for quite large items.

If you want better surface finish, then try coating the polystyrene in plaster for a smoother finish, then simply bury the item in play sand and cast directly as shown at buildyouridea

Just some more ideas for the pot

[Neil WyattModerator @neilwyatt]

Why does someone who takes such care to get their castings right pour molten metal with some in shorts and trainers just a foot away?

[ZebethyalParticipant @zebethyal]

I believe the person in shorts and trainers is actually Dave Kush himself, the author of the website, obviously personal H&S is not high on his priority list.

[Ian S CParticipant @iansc]

This is the way it should be done (Japan about 120 years ago).

Ian S C

[Author]

Posts