A newbie to Additive Manufacturing 4

[arunmrao]

I am old school boy, spent all my time with furnaces and sand moulds. Now, metal casting industry too has been taking advantages of this new technology.

I recently attended first Additive Manufacturing Technology for Metal Casting by American Foundry Industry. I was overwhelmed seeing the developments being done in the areas of pattern making and sand moulding.

To cut a long story short, we have now bought a FDM machine for PLA and ABS materials. This equipment, we plan to use for pattern making and with the experience gained move towards sand printing.

I invite suggestions and advice from experienced members about the potential pitfalls that I must avoid . The machine is from Titan 3D robotics.
CEO of the company will be traveling to Nigeria to instal and train the staff.

Thanks for patiently reading a long note.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[itsmoked]

Yay, welcome to the club Arun.
Got a link to your particular Titan?

Don't breath the ABS fumes.

I use this program simplify3d for my CAM aspect when I need support under a part which sooner or later you'll need. It works pretty well and did a great job for me on a really weird shape that needed odd support.


In your foundry are you planning to use this printer as a way to make the positive for your sand molds?

Really much harder than the 3D printing is coming up with a program to draw 3D objects. I'm using Fusion 360 which is heavily supported and free as long as you're not making too much $$ with it. Certainly a place to start at. Watch the tutorials on YouTube, there are a million.






Keith Cress
kcress -

http://www.flaminsystems.com

 

[arunmrao]

Thanks Keith, Yes we are planning to make the patterns (positives of the mould) using PLA and ABS. I had seen them being made in US and then only replicated them here. Univ of Northern Iowa at John Deere Centre has a very good integrated facility and I was privileged to visit them .

The website is

http://www.titan3drobotics.com.

Clay Guillory is the CEO and recently he demonstrated a multi head 3D printing machine Cronus, which can now reduce print time for large objects.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[MacGyverS2000]

How close do the plastic parts need to be to the original? Minor shrinkage is a concern, as well as patterning due to the manner of extrusion. You can smooth the pattern out with an acetone vapor bath, and shrinkage can be handled by proper part design and tweaking.

I can verify they work well for lost wax style casting, though.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[arunmrao]

I saw a few patterns in both materials, the finish of patterns was acceptable for sand moulding. But ,in another investment casting foundry, they have a battery of these machines being used.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[JNieman]

We have machined a lot of castings done through "lost-plastic" casting before the customer wanted to invest in hard tooling. The two issues we've had are:

1) Large, thin, flat surfaces are more needful of reinforcement/stiffeners to prevent warpage. Temperature control during printing can make or break some geometry, as the plastic cools, it moves, so controlling and limiting this is paramount. It seems to move faster when it cools quickly, before subsequent layers of plastic can be shot down.

2) We've had periodic issues with remaining plastic inclusions. We've scrapped parts because we drill and tap holes, only to find that a significant portion of the machined thread was plastic, where it hadn't completely melted out, I suppose.

3) Material choice is important. PLA has a melting point significantly lower than ABS but I don't know if they flow any differently. You're bound by the two limitations anyways. But I would assume you want to go with PLA as it is slightly more thermally stable than ABS, during cooling, and has a lower melting temp.

4) Shrinkage might have to be calculated from scratch. It won't be like metals obviously, but the "rules of thumb" (or should it be rule of the wrist?) go out the window since it's such a different material.

Good luck. I'm certain it'll be a great success. What machine did you get if you don't mind me asking?

I recently attended a seminar in hopes of learning about some new materials and methods in order to start printing fixtures and workholding devices off-line. There were significant segments of the seminar focused on injection molding, which were interested. FDM process creates the actual mold, which allows different other plastics to be injected. Mold made from some kind of thermoset plastic, then you can use some common thermoplastics to inject for the part, including HDPE, which I thought was pretty nifty. Not very applicable in my workplace though. BUT.. I'm assuming they go through comparable thermal calculations to prevent similar issues as you would.

 

[arunmrao]

Thanks Jnieman for your insights. PLA material has lower melting point, but its wear resistance properties is poor compared to ABS. Sand being very abrasive can reduce life of the patterns.
It certainly will be a learning curve for us, the hard way.I performed a destructive test ( using a heavy hammer) on some PLA patterns and they withstood the impact.
American Foundry Society : Additive Manufacturing for Metal Casting Committee held a 1 day conference on Jan 25th at GE CATA. I followed the minutes of the meeting.

I too have some concerns regarding holes, shrinkage pattern, warpage etc .

The recently awarded Oscar statuettes were manufactured using 3D printing in a art studio ( Polich Tallix) in New York. They have also Faro arm, investment casting facility, gold plating, etc. Some day I shall visit their facility .

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[JNieman]

I had assumed the PLA pattern was a one-time use, investment casting situation, rather than being a re-usable pattern. My mistake. I would definitely look at it differently as well.

I'm curious if anyone is employing acetone vapor baths to smooth surfaces for situations like yours. Maybe the smoothing of the surface is accomplished by other means. I don't know how, or if, one could control the surface smoothing in an acetone vapor bath. I've always been skeptical but also curious if a controlled process can yield repeatable results.

 

[MacGyverS2000]

You can purchase the acetone vapor baths from more than one of the major 3D printer manufacturers. I rolled my own and used it for a short while... the results were impressive when comparing before/after. Had I needed it for more lengthy work, I would likely have improved control of heating/cooling of the vapor.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[itsmoked]

JNieman; Arun said in a prior post that it was the "Cronus" actually I believe it is called a "Titan Cronus".

The link to the site is above. Be forewarned the website clings to the recent paradigm of moronic ratio movement and in a nutshell is one giant pile of useless unintelligible crap. I would never consider buying anything from a company with a website that horrid and insulting.

Luckily Arun probably got to lay hands on the Cronus and talk to the staff directly before laying out what must've been a suitcase full of money.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[itsmoked]

For lost casting you guys can actually use PLA directly?? Not some wax type filament?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[arunmrao]

Yes, one can use PLA directly and and firing at 350C burns off the PLA material, leaving behind the ceramic shell.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[itsmoked]

That's pretty sweet as PLA prints very easily.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[arunmrao]

Stars to all you gurus, for encouraging my baby steps in 3 D printing.I learnt a few things. I shall come back with a picture of 1st 3D print pattern.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[JNieman]

*bump*

@arunmrao

How's the journey been so far, if you don't mind me prying.

I've successfully integrated 3d Printing tooling into my company's 'technology roadmap' and eagerly await my turn when it fits into our scheme of investment. I'm pretty sold on Titan. Unless someone comes in and disrupts the market of professional grade FDM machines, I believe Titan has the best thing for shops like ours. (the Hyperion specifically)

Also I like their company story, since I spent a lot of time in Lafayette, LA, am familiar with a lot of ULL engineering grads, and know the 'culture of technology' the city-parish supported.

 

[arunmrao]

@JNieman,

Thanks. Next week commences our journey, when Clay would be around. It is certainly exciting time here, and our young Nigerian engineers eager to learn.

We have also added a 12' Faro arm to the family in our quest to go digital. I shall post some pictures of our first digital print.

It is good that the site management has merged 3D printing with Additive Manufacturing, making it more encompassing..



"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[arunmrao]

I have finally installed the 3D printer and the first print is out. A sand casting pattern in PLA, printed in 37 hours! compared to 3 weeks of traditional route.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[itsmoked]

Very Nice! That should get you into the next age of sand casting.

um, that's a nice looking place that doesn't fit with any of my casting foundry experience. LOL

Is that air tank associated with the printer??

Keith Cress
kcress -

http://www.flaminsystems.com

 

[arunmrao]

Thanks. It is just the beginning, soon I shall be pushing for the more intricate ones and extending it to make investment cast parts.

You are right, it is a air tank. However air requirement is very small. It is used for keeping the arm in place without falling off.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

 

[JNieman]

Very cool!

37 hours for a part that size is pretty impressive, I think! That machine has a pretty good flow/throughput it seems. Looks great.

Thanks for the update.

Good on you for the Faro Arm investment. We have a Romer Arm that's proved invaluable for parts of a certain size. We have two large gantry touch-probe CMMs that would easily do your part (for size reference) and several manual probe CMMs but for small parts, it's often easy enough to probe-scan them. Once they reach a certain size and complexity, though, laser/probe scanning with an articulated arm CMM proves GREAT savings in time as well as getting much more data (points collected) and so long as the precision allows it... the Romer Arm really speeds things up without adding risk or guesswork.