Category: Additive Manufacturing

Fatigue Life of Additive Manufactured Aluminum

Thanks for the comments & questions regarding Additive Manufacturing (AM) and material properties. Our motto, see below, really is our mission statement. We learn when you send us problems.

Today we post a video reporting on material properties of AM build aluminum parts. To maximize the material properties of aluminum requires alloying and heat treatment. Typical aluminum welding wires are either silicon alloy 4000 series or magnesium alloy 5000 series, neither of which is heat treatable. Brian Harrison with Alcotec Wire Co graciously supplied a spool of heat treatable copper alloyed 2319 wire. After solution heat treat and aging, we measured tensile strength at 63,000 psi. This means you can use AM to build an aluminum part with the strength of steel and 1/3 the weight.

Next, we built a 5356 aluminum test specimen using AM for fully reversed cyclical fatigue testing at 70% of the tensile strength (130% of yield). The part survived 5,500 cycles. Less than a heat-treated 6061-T6 part but not bad. This is useful data as we build our reference library of AM material properties.

At ARC Specialties we thrive on problems, send us yours!

Additive Manufacturing using High Strength Steel

Additive Manufacturing with High Strength Steel
or Tensile Testing the Texas Way

For Additive Manufacturing (AM) to become a mainstream technology finished material properties must match typical nominal values. You should never assume that a metal AM part will be as strong or durable as a cast, forged, or fabricated part. We seldom see hard data on mechanical properties of AM parts which makes me skeptical. This post is another addition to our ongoing reporting of real material properties along with a little fun.

To explore the upper limits of material properties we decided to build high strength low alloy steel parts using a FANUC America Corporation robot a Lincoln Electric pulsed GMA welding system and high strength Midalloy Specialty Materials, LLC. ER140S-G welding wire.

We are learning some tricks to enhance material properties of AM built parts and we used all of them. After welded we tested the part AS-BUILT without post-weld heat treatment or stress relief. The results exceeded our expectations, but you have to watch the video to get the numbers.

Spoiler Alert: we achieved yield and tensile strengths TRIPLE that of mild steel!

Just Truss Me: Wire Arc Additive Manufacturing

We decided to build a truss to see just how strong Wire Arc Additive Manufacturing (WAAM) built aluminum parts really are. Mike Willey created a truss design and used FEA to estimate that it would support over 1000 lbs. Kevin Sevcik then imported the model into Robotmaster offline programming software to create the robot path. Then using Lincoln Electric R350 Power Wave with Advanced Module running in AC pulse mode Jim Walker built a 5356 aluminum truss using the ARC-06 robot in our laboratory. Total build time was around 3 hours and for an 8 pound part. Finally, we tested the part in our own special Texan way to over 1,200 pounds WITHOUT FAILURE.

Watch the video for the whole story:

ARC Specialties thrives on problems, send us yours!

Additive Manufacturing (AM) with Aluminum

We have received requests for aluminum AM parts. Last week we developed the technology to build 3D aluminum parts using a FANUC America Corporation robot and a Lincoln Electric R350 Power Wave with Advanced Module running in AC pulse mode.

As we refined the process parameters we were pleasantly surprised to find that the best results coincided with higher wire and travel speeds. As productivity increased so did build quality. My professor once taught me that a small weld puddle has sufficient surface tension to negate the force of gravity. He was right. We are able to build horizontal just as well as vertical!

After welding & motion control the final piece of the AM puzzle is programming. We are working with Gregory Culp and the Robotmaster team to slice cad models and generate torch path and orientation to build complex 3D parts. Being able to build horizontal complicates programming but greatly expands feature build capacity.

The build parts have passed Liquid Penetrant (LP), side and face bend tests. UTS and YS, R of A and %Elong are typical for 5356 alloys.

If you have an aluminum part you would like to build with AM, contact me.


ARC Specialties thrives on problems, send us yours!

Dan Allford