Dimple cracking caused by laser cut holes

[gotyoke]

Used to be all your final-sized holes were punched, you would knock off a slight burr, and be good. Now that Van's is using laser cutting, each and every hole has a notch. Eliminating the notch requires deburring to such an extent that it would oversize the hole. So instead, you just have to deburr as much as you are willing, and hope the hole doesn't crack when dimpled.

Well, here's what hoping will get you



Come on, man!

[Tommy123]

Ugh. That is unacceptable.

[Marc Bourget]

If the notch exceeds the .125 dimension, I would request an RMA and replacement. If quality work, you can anticipate a 30+ yr lifespan granting you a decent ROI.

I'd question that service-life estimate if a notch is present.

[lipper03]

Agree, I’ve replaced at least one laser cut part, and still had some light file work to do after reaming and dimpling. It the ones I couldn’t see that worry me as well.

[RV7A Flyer]

How about a "before" picture?

[lipper03]

I have one, this is as received, even has burn marks. Had to ream and even then, had to pull the reamer to the notch side to clean up the nick. Watch your laser cut parts carefully!

[Tlrguy]

I’m also seeing holes that contain the little notch depicted in the picture above. I guess I haven’t really thought about how much notch is unacceptable? I understand a cracked dimple is grounds for replacement, but what about the ones that don’t crack initially? What are the odds we are going to be seeing an influx of crack repairs coming from the Mothership in the next 5-15 years?

[gotyoke]

Originally Posted by Tlrguy

I’m also seeing holes that contain the little notch depicted in the picture above. I guess I haven’t really thought about how much notch is unacceptable? I understand a cracked dimple is grounds for replacement, but what about the ones that don’t crack initially? What are the odds we are going to be seeing an influx of crack repairs coming from the Mothership in the next 5-15 years?

I admit that I am worried about this. I'm not 100% festidious about addressing the little notches, as you can see in the original picture, because it would be literally every hole. I deburr, but nearly always a small notch remains. Final drilled was supposed to mean hole prep work was minimal. Addressing these laser cut holes may turn out to be nearly as bad as having to match-drill everything.

[Tlrguy]

Originally Posted by gotyoke

I admit that I am worried about this. I'm not 100% festidious about addressing the little notches, as you can see in the original picture, because it would be literally every hole. I deburr, but nearly always a small notch remains. Final drilled was supposed to mean hole prep work was minimal. Addressing these laser cut holes may turn out to be nearly as bad as having to match-drill everything.

I share your same concern. My current -10 build is my first RV and I am starting to think these laser cut parts are going to be problematic in the future. It is completely unrealistic to dress the notch out of every single rivet hole. Most of my laser cut holes are pretty clean but they all possess a little”pool” of what appears to be once molten metal.

I sure hope these airplanes started in the 2022ish timeframe don’t end up being known as “Covid Era” builds with airframes riddled in stop drilled holes and ultimately undesirable on the resale market.

[KeithO]

They are using a bad strategy with the cutting. They should start close to the hole center and then spiral outward, that would not give a notch. Someone is saving a fraction of a second in cycle time by starting at the major diameter and then creating notches on every hole. A strong message needs to be sent to management.