Now I being to understand the scale of the problem.

Laser cuts by heat. The temper of the metal at the cut edge will change. It will become brittle and loose ductility, become hardened. This will cause cracks when it is yielded, like forming dimples.

Water jet cuts by abrasion. While that can also cause heating, the water itself cools the cut so no loss of temper occurs. The material properties are basically unaffected. I don't know if thin 2024 aluminum can be cut by water jet, but it seems like it should work.

To salvage laser cut aluminum, you would have to anneal the part again. For large pieces, you will need a big oven. You need to heat it up to about 600 F for perhaps an hour or two.

Once annealed, the temper is lost for the entire piece. So if is was 2024-T3 before, it is no longer T3 temper. This could affect the properties of the metal enough that it no longer meets the design objective.

This is a mess and could prove to be an existential threat to the company depending on how much money is sunk in unusable parts, and the customers with planes fully or partially built with the bad parts.

Mike C.

If this is true, then why would Van’s say they had one testing that showed this method would be acceptable?

Van’s doesn’t seem like the kind of company that would lie about something like this. Their existence relies on maintaining a good reputation and manufacturing a good, safe product.

It’s hard to envision that there’s any scenario other than the vendor produced parts using a method, material, or quality that was inferior to what was tested.

Yikes! Mr. Ufkes

If you zoom in and look closely at the holes on each side of the dimpled hole there appears to be a small notch on the upper side of each hole. Is that notch where the laser makes the initial plunge into the material and it over burns the hole a bit?

The orientation is similar to where the dimple is cracked. Could it be a programming issue vs a laser heat issue? If the laser started in the center of the hole and spiraled around to the outer circumference of the circle could that stop the problem? It wouldn't help on parts already made but might explain why it's dimple hole problems and not a problem on the bends?

It's going to be hard to test to find out if 200, 500, 1000 hrs later there might be widespread airframe issues. I'm sure Vans wants very much for the company to find no issues. I'm not sure how they would test that because the skins are under tension and/or also lifting away from the wing ribs or bulkheads. The vibration cycles would depend on 2/3 blade prop, RPM, airframe use (aerobatics or high speed vs normal cruise) and airframe location. Lots of variables.

Belly skins and inner wing root areas might be helped with some stick on dampening panels like Cessna had used.

The RV3,4,6 could be plans built. Do layout drawings, plans or patterns come with any of the current kits or are they dependent on factory produced, cut parts and only come with assembly instructions? Down the road if Vans is gone can these parts be replicated if needed?

No skins were laser punched. All of the laser cut parts are internal structure like ribs and stiffeners. The tool path is/was a big part of the issue. Someone decided to start the entry hole on the perimeter of the hole(s). Not sure who, but it needed to start in the middle and spiral outwards. The initial penetration caused a divot in the edge of the hole(s), which is where many/most/all of the cracks are beginning.

Which means that all the stuff being said with "absolute certainty" that this is an issue of HAZ and tempering should not be so certain, I supppose.

The problem is that if everyone is "absolutely certain" all laser cut parts will crack, nobody will be happy if the science proves and they are told, "yes, that is a laser-cut part, but the tool path was correct and you have no signs of the laser "start notch" in your holes. Follow proper assembly techniques and you will be fine."

It's like cyanide in a few jars Tylenol; the shelves have to be cleared nation-wide.

Here is a citation from a testing document on laser cutting aluminum alloys:

".. Decrease in hardness was observed up to 300 mm into the material due to the destruction of the thermal treatment prior to the processing, as a consequence of the thermal input during cutting. Scavino et al. [28] also performed microhardness measurements on the same alloy and detected a lower reduction in hardness after cutting. Araújo et al. [27] performed a study on the HAZ formed during CO 2 laser cutting of the 2024-T3 alloy. ...
... This was attributed to the roughness of the cutting edge, which promotes crack initiation. Scavino et al. [28] also performed an evaluation of the mechanical properties of machined samples of 6061-T6 and 6082-T6 alloys. Tensile and bearing tests showed that mechanical properties were found in the range of international design standards. ..."

https://www.researchgate.net/publicatio ... properties

If you look at the last sentence it seems possible under ideal conditions to meet design standards cutting with a laser. I imagine this is the kind of research that Van's is using for the argument that the parts can meet spec.

However, what is possible doesn't mean it should be done. Look at all the challenges aviation companies have had building composite structures that were supposed to be so much better and cheaper than aluminum. One of the oft mentioned arguments for aluminum in a home-built aircraft like Van's.

Seems like just a really bad decision when there were better much more forgiving cutting alternatives. Unfortunately the company still hasn't admitted this was a huge mistake, which makes me wonder about their future.

I'm not going to argue that laser cut parts were a good idea or there was a QA, management, and engineering breakdown over the decisions to bring in a new process without strict controls.

What I will say, is that most of vans parts are meant to be final drilled. Meaning - the holes, either formed from a punch or laser, are undersized at the factory. During assembly the builder match drills the assemblies. Now of course we are talking a few tenths here and the HAZ for aluminum can be large based on a number of factors. But I think the logic was that final drilling operation would clear out the inconsistent laser hole eccentricities and HAZ (high thermal conductivity in Al). Also note a majority of the laser cut parts were low stress areas. Spars, longerons, etc were still conventionally punched/drilled. So provided the laser lead in and plunge was done correctly (doesn't appear it was), it sounded like a good idea on paper to meet demand. Now is the painful part to restore your reputation and get your business side of the house in order.

No doubt the company they contracted this to should have known this, and 100% Vans should have known this when the spec'd and sent the PO for these outsourced parts.

Hopefully they will overcome this and can retain the employees.

Why didn't he express his concerns before accepting the parts?

I waterjet a variety of materials including thin aluminum. I outsource a small amount of laser cutting. Why laser? - its faster, and the material comes out cleaner. After the waterjet process the material will be full of sand and aluminum particles post cutting. Washing off a flimsy sheet of material can take longer than it does to cut it, especially if you do not want to scratch it.

When we waterjet aluminum we always cut holes undersize. They are spotted holes that we open up later. No matter how slow you go the surface finish of the inside of the hole is not smooth. In material thicker than 3/8" the hole is not round on the side opposite the nozzle.

If I were going to build an airplane with waterjet, or lasered, parts I would cut all the holes undersize, then drill them open. If they were in a stressed piece I would also ream them and then set up a depth limited countersink to 45° the upper and lower edges of the hole by a small amount proportional to material thickness. The goal here is to have a perfectly round and smooth hole with no sharp edge on either side.

As pointed out a few posts above, I thought that this was how Vans was doing this. If this were the case the initial fabrication method should not have much effect.

FYI - Watejeting material is not a "cool" process. Like any grinding operation it creates heat. I've watched some materials (not aluminum) get red hot around the cutting stream. Wildly different amount heat than melting the material though.

Process control is hard.

I hope Vans survives this intact.

Its not just the issues they have stated as the cause of concern, although they are bad enough.

Vans also changed their internal kit assembly for shipping process. Before they would pick kits in the order in which they came in. Now during (Jan 2022) this they moved to a process where they would be picking all of a kit type say RV-14 wings and doing large batching processes for those, then moving to RV-8 wings, then RV-14 fuselage etc.. The stated purpose was lower the expected wait times, but I wonder if it was a rather a function of cash flow rather than efficiency? Could this change have affected cashflows throughout the company.

[youtube]https://youtu.be/KMTkDq2g-p0[/youtube]

[youtube]https://youtu.be/KMTkDq2g-p0[/youtube]

The primer issues on the overseas construction of quick build is a significant issue as well.

One thing is certain... kit prices are going up.

As will completed examples

As will completed examples

older ones, but recent completions now have a cloud of suspicion over them