Category: Systems

Be Narrow Minded

 

I’m a long time advocate of narrow gap welding. The advantages are tremendous, but the challenges are too. A 5″ thick standard V Butt weld with a 75 degree included angle has five times the weld volume of a 1″ wide 5″ Square Butt. This means a narrow gap joint would have five times less weld wire, five times less arc time, much less distortion. And fewer defects because every inch of weld that you don’t make is an inch you don’t have to inspect and possibly repair.

Why isn’t narrow gap the standard technique for welding heavy sections? Because the technical challenges of welding vertical walls in confined spaces are huge. For good sidewall fusion, the arc must impinge on the walls. Otherwise, you risk lack of fusion defects at the bond line. Our new Narrow Gap Hot Wire Torch features a servo tungsten electrode oscillator to point directly at the sidewall. That is only half the battle. The wire must follow the tungsten. We did just that using a second independent servo this allows us full control of arc and the filler wire position. Finally, we use our HOT ONE AC constant voltage hotwire system to double the deposition rate, which cuts weld time in half.

To see a video including Xiris Automation Inc. arc monitoring click: https://lnkd.in/eBTHYgh

It Depends

 

Is the answer I dread when I ask a technical question. Unfortunately when customers ask: “How accurate can you plasma cut parts with a robot?” I reply: “It depends”.

Recently we were asked to cut 1.575″ (40mm) holes in 3/16″ plate with a circularity of +/-.005″. This is a tight tolerance for plasma. Normally we would have recommended laser cutting. But I tell people that a watt of electrons is much cheaper than a watt of photons. Plasma has a number of advantages over laser: system cost, power efficiency, maintenance costs, and safety.

So we went to the lab to explore the limits of robotic plasma cutting. What made this project unique and doable was the fact that hole position tolerances were achievable. Our challenge was hole shape and size. We used a Hypertherm XPR300 High Definition Plasma and a KUKA North America robot. Jim Walker & David Luce programmed the cut in small segments to optimize torch path and cutting parameters and cut holes +/-.005″.

BUT your part accuracy depends on many variables. In the video, I stick out my neck and QUANTIFY best, worse and typical effects of 7 issues on part dimensions. This should start an argument!

ARC Specialties thrives on problems, send us yours!

Match of the New Millennium: Man vs. Machine vs. Robot

 

In manufacturing, these are your only choices. Fortunately, there is still a place in the world for people. Some things humans do best. Any task which requires flexible adaptation to unpredictable dynamic environments is a good example. But sometimes the best man for the job is a robot, or possibly a machine.

When your only tool is a hammer the whole world looks like a nail. When your system integrator is a robot house you should expect a robotic solution. Over the last 30 years, robots have become faster, more reliable, cheaper, and easier to integrate and operate. So, we use ‘bots on an ever-increasing percentage of our systems. But not always.

Sometimes the best solution is a purpose-built machine. The reasoning may be a smaller footprint, or maybe you don’t need 6 axes of motion or standard robot software won’t fit your needs. What I have found over my 40 years of building machines is that a purpose-built machine is typically faster and more precise than a robotic solution. Today’s video showcases two welding solutions that my team decided to automate with an ARC Specialties purpose-built machines.

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

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!

Series Arc | Research & Development

“History doesn’t repeat itself but it often rhymes,”
–Mark Twain

Our Additive Manufacturing (AM) posts on high deposition welding processes have generated a lot of interest. I was even invited to submit a paper for consideration at Solid Freeform Fabrication Symposium. With electroslag strip, we build parts up to 2 1/2″ wide and 3/16″ thick in a single pass. With submerged arc, we deposit 30 pounds per hour or more!

These are the old welding processes that us old guys have used for years.

In today’s video Dave Hebble demonstrates a twin wire variation of submerged arc welding (SAW). Series arc has a number of unique and useful characteristics. First is you don’t need to ground the part, something we find useful when the AM built part is manipulated in a 2 axis positioner. As well as remarkably high deposition rates and wide flat weld beads. But I will let Dave explain it all in the video.

 

When I started my career in the late ’70s I was fortunate to have Dave Hebble as a mentor. Dave is the best welding process engineer I’ve ever met. 10 years ago he joined us at ARC Specialties. When people ask what I have Dave working on I respond that: “It is not right for the student to tell the teacher what to do”.

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

“Collaborative Robots: What are they and when to use them.” AWS Houston

On Wednesday, October 16th at 7:00 pm, Dan Allford lead a session at AWS Welding Houston.

Collaborative robots or cobots are designed to be safe to work near people.

This unique feature opens up new applications for robots. One of these areas is welding and plasma cutting. Using case studies, Dan discusses where cobots might be applied and where they should not.

Download the Presentation

“Why Robotics: How to Ensure Your Project Makes Economic Sense” – 2019 AWS Welding Summit

 

On Thursday, August 30th at 11:00 am, Dan Allford lead a session at AWS Welding Summit 2019.

“When correctly applied robots save money and improve quality. When misapplied the robot becomes an expensive dust collector. Using case histories Dan will discuss how to determine when and if a project is economical to automate. Topics include initial robot cost, programming costs, filler material savings, safety, part accuracy, joint configuration, production volumes and technological competency necessary to succeed.”

Download the Presentation