Model 3 Spot Welding FUD

[Vitold]

I read two articles today, "Silicon Valley is struggling to understand Tesla's Model 3 production problems — here's why" that is referring to article in Automotive News that is supposing that Tesla is having issues spot welding steel):

"Resistance welding should make a little smoke, but when you see stuff popping out like that, that's called expulsion," automotive manufacturing consultant Michael Tracy of Agile Group in Howell, Mich., said of the first video. "It's symptomatic of weld spots getting too hot because they're poorly planned, or in this case, the metal not being pulled all the way together."

I looked up youtube videos of robotic spot welding and they all have sparks flying (expulsion):

Vovo:

Toyota:

BMW:

Tesla:
Instagram post by Elon Musk • Oct 8, 2017 at 10:20pm UTC

 

[voip-ninja]

That would also line up with the 1/10 speed the robots are working at in the video that Elon shared.

Tesla does understand how this process works as they have numerous people with experience in this area working for them including former top executive of Volkswagen Audi Group.

My immediate suspicion would have to be that the video that was shared was of the actual process of tuning the assembly robots... which includes doing test welds and then making adjustments to the position of the robots as well as the position of the parts.

I don't know how quickly this process can be done but I would imagine it takes weeks not days to do in order to eventually start doing large scale production.

Looks like we will be lucky if the first external customer deliveries make it this year but would love to be wrong.

 

[voip-ninja]

Mods please merge this with the other thread about welding as that one includes the full WSJ article or at least main excerpts.

 

[North75]

They might be having issues welding some of the ultra high strength steel grades they are using. I've read some articles about issues welding some of these new grades of steel. I don't know which grades Tesla is using on the 3, but it wouldn't surprise me that they are unique from grades used in the S and X since they used mainly Aluminum and only a small amount of high strength steel.
I'm sure they will figure it out eventually if they haven't already.

 

[voip-ninja]

Also, to the OP, the issue that the industry expert had was not with the sparks seen in Musk's video of the welding, it's the amount of smoke being expelled during the welding process, which is not normally seen.

I think it's quite a stretch to brand this FUD because you don't agree with it or don't understand what the issue is.

 

[Vitold]

Also, to the OP, the issue that the industry expert had was not with the sparks seen in Musk's video of the welding, it's the amount of smoke being expelled during the welding process, which is not normally seen.

I think it's quite a stretch to brand this FUD because you don't agree with it or don't understand what the issue is.

Sounds like you misunderstand what it supposed to be happening. It's not the smoke but material expelled from the weld and, as you can see in the videos, some is unavoidable.

Expulsion is an undesired event during resistance spot welding because the weld quality deteriorates. It is the ejection of molten metal from the weld nugget which usually occurs due to applying a high current for a short welding time.

 

[voip-ninja]

Sounds like you misunderstand what it supposed to be happening. It's not the smoke but material expelled from the weld and, as you can see in the videos, some is unavoidable.

So Micheal Tracy who complained about the amount of material being expelled (and he specifically cited smoke) doesn't know what he's talking about?

Okay, maybe.

Since he works in the industry I would have assumed he had some reference type.

Sparks during welding are normal and he didn't appear to be referencing that.

 

[gregincal]

So Micheal Tracy who complained about the amount of material being expelled (and he specifically cited smoke) doesn't know what he's talking about?

Okay, maybe.

Since he works in the industry I would have assumed he had some reference type.

Sparks during welding are normal and he didn't appear to be referencing that.

By my reading he said smoke is to be expected, and is complaining about "stuff popping out" which certainly doesn't sound like smoke. Where is the quote where he is talking about about the amount of smoke?

 

[voip-ninja]

By my reading he said smoke is to be expected, and is complaining about "stuff popping out" which certainly doesn't sound like smoke. Where is the quote where he is talking about about the amount of smoke?

Yes, I re-read it again and it seems you're correct, here's the quote below, not sure what he found objectionable but he does work in the industry so would be interesting to get a more detailed take on what he's objecting to that he's seeing in the shared clip.

"Resistance welding should make a little smoke, but when you see stuff popping out like that, that's called expulsion," automotive manufacturing consultant Michael Tracy of Agile Group in Howell, Mich., said of the first video. "It's symptomatic of weld spots getting too hot because they're poorly planned, or in this case, the metal not being pulled all the way together."

 

[MP3Mike]

What I think is most interesting is that he reports to know exactly what the reason is from the video. "or in this case, the metal not being pulled all the way together."

Could he really see that much detail in the video?

 

[jhs_7645]

What I think is most interesting is that he reports to know exactly what the reason is from the video. "or in this case, the metal not being pulled all the way together."

Could he really see that much detail in the video?

I could not find much information about Michael Tracy of Agile Group (other than "Agile Group" is a company of one, and has been for 23 years). Aside from his membership in various consortiums and industries, I couldn't find where his expertise comes from. Grain of salt perhaps.

 

[voip-ninja]

I could not find much information about Michael Tracy of Agile Group (other than "Agile Group" is a company of one, and has been for 23 years). Aside from his membership in various consortiums and industries, I couldn't find where his expertise comes from. Grain of salt perhaps.

If someone disagrees with his analysis or believes it to be FUD they could probably try to contact him for more details on his observations.

 

[jhs_7645]

If someone disagrees with his analysis or believes it to be FUD they could probably try to contact him for more details on his observations.

If the original article was properly sourced and written (two sources -- establish their credibility), we wouldn't have to follow up with what should be basic journalistic practices.

The importance of fact-checking for journalists

 

[jelloslug]

If someone disagrees with his analysis or believes it to be FUD they could probably try to contact him for more details on his observations.

When car manufacturers want to show off welding robots, they crank up the current and have a fireworks show. The reality of spot welding is nothing more than a red glow and a wisp of smoke.

 

[voip-ninja]

When car manufacturers want to show off welding robots, they crank up the current and have a fireworks show. The reality of spot welding is nothing more than a red glow and a wisp of smoke.

Then perhaps the analysts comment about too much expulsion is correct.

 

[jelloslug]

Then perhaps the analysts comment about too much expulsion is correct.

Yes, he is correct about the expulsion but to assume that it's happening on all the cars is highly unlikely. I have been in many assembly plants from many different manufactures and tier one suppliers and a spark show is just that, for show.

 

[jelloslug]

To clarify my position on spot welding: I'm an engineer in the industry and I do have a fair bit of knowledge of spot welding.

 

[JeffK]

When car manufacturers want to show off welding robots, they crank up the current and have a fireworks show. The reality of spot welding is nothing more than a red glow and a wisp of smoke.

You're not always going to avoid sparks... here's a video of both, but I doubt they were specifically made to spark.

 

[jelloslug]

You're not always going to avoid sparks... here's a video of both, but I doubt they were specifically made to spark.

True, it's very difficult to completely eliminate expulsion in automated spot welding but a giant spark show is done deliberately. I can also tell you that the second set of welds in that video need more work on the robot programming.

 

[voip-ninja]

To clarify my position on spot welding: I'm an engineer in the industry and I do have a fair bit of knowledge of spot welding.

So what's your analysis of the Tesla welding video.