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Van's part fabrication process

Palamedes

Palamedes

Well Known Member
In my "RV-15" thread someone made this comment;

I also wish that Van?s would improve their production process of the metal parts. I recently had chance to check out Zenith and Rans kits ? much less, if any, deburring required. I understand that they use a different process than Van?s to cut the metal parts.
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What is the process?

What are the different processes that could be used?

Why would another vendors process maybe be better?
 
Water Jet

As I understand it, Van's punches all there parts with dies in some sort of press. I further assume that this is a two step process (punch then form). With the forming likewise being accomplished with a set of dies in a press.

The first alternative that comes to mind is CNC style water jet cutting. As this process uses an abrasive material in a stream of water. This would essentially "sand" smooth the edges of parts as they are cut.

Others more familiar with this process may be able to provide additional details/corrections.
 
I *think* the reason we have to deburr is because we have to match drill the holes. The drilling creates the burrs. Van's chooses to undersize the holes which means we have to match drill. There is some good benefit to this, as it means our parts will have much better fitment because we match drill them just prior to assembly.

If match drilling wasn't done, there is a possibility that the holes could get misaligned from slight bends or even temperature changes. This could lead to some oil-canning when final riveted.

Even though its a bit more work, I think I prefer the match drilling / deburring procedure because it assures perfectly matched parts, every time.
 
CubedRoot said:
I *think* the reason we have to deburr is because we have to match drill the holes. The drilling creates the burrs. Van's chooses to undersize the holes which means we have to match drill. There is some good benefit to this, as it means our parts will have much better fitment because we match drill them just prior to assembly.

If match drilling wasn't done, there is a possibility that the holes could get misaligned from slight bends or even temperature changes. This could lead to some oil-canning when final riveted.

Even though its a bit more work, I think I prefer the match drilling / deburring procedure because it assures perfectly matched parts, every time.
Click to expand...

We're talking about the edge deburring, not deburring holes. That is, smoothing out the little "serrations" along the perimeter of parts and skins, as well as the edges. That's my #1 most-disliked task, followed closely by cleaning and priming.

I will say, having used a waterjet before, you're still going to want to smooth the edges manually, unless you have a different kind of machine than the one we used. I'm also not sure you'd be able to hold quite the same tolerances. But then, I rarely cut anything thinner than .063 on the one I was using.
 
i understand that vans uses cnc punches to cut parts. as someone that does that kind of work in a production shop i understand a bit about it.

water jets do produce a near paint ready part. however, they have big drawbacks is speed of production and cost. the equipment is very expensive compared to turret punches. the expendable are also a cost factor. for a small production run the time difference is not that big of a factor, but for a large run of parts it can be a big difference.

im sure that vans has done all the figures to see what is the best way to go for their production numbers.

one of the biggest things i see is that people over de-burr parts. all you need is no ridges that can cause a stress riser. i have seen people using muti grades of abrasive up to 1000 grit. A quick pass of the scotchbrite wheel or pad is enough on most sheet to clean up the edges.

bob burns
RV-4 N82RB
 
rmartingt said:
We're talking about the edge deburring, not deburring holes. That is, smoothing out the little "serrations" along the perimeter of parts and skins, as well as the edges. That's my #1 most-disliked task, followed closely by cleaning and priming.

I will say, having used a waterjet before, you're still going to want to smooth the edges manually, unless you have a different kind of machine than the one we used. I'm also not sure you'd be able to hold quite the same tolerances. But then, I rarely cut anything thinner than .063 on the one I was using.
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Ah gotcha! Yeah, edge deburring is a pain in the butt. The parts that drive me bonkers is the little grooves where the flanges have the relief cuts in them. I wear out scotchbrite pads trying to get those edges smoothed out. The skins especially need some extra work on the edges. The shear marks are pretty prevalent on some of the parts. I have had to use a file on some of the shear marks just to get them level, before I could scotchbrite them.
 
51% Rule

I think you have to be pretty careful anymore and Van probably has some trouble making sure the 51% rule is met. I think they intentionally leave much of the non-critical issues like deburring just so that there is some visible work that will add up to 51% of the manufacturing rule for homebuilt experimentals.

While it seems kinda small, Vans has done so much work in the Kits that it's almost a stretch to say that we do more than 51% of the work. The evidence of that is in the completion rate of late model kits compared to "kits" from 15 and 20 years ago...

Just saying ..... the 2,000 hours the average builder puts in probably wouldn't come close to covering the time required if you had to actually fabricate all the parts. The part done in the kit represents a LOT of working hours.

Just my .02 .... when I built my 7 back in 2003-10 I was amazed at the amount of work I didn't have to do :)

500+ hours and still grinning :D:D:D
 
BillSchlatterer said:
I think you have to be pretty careful anymore and Van probably has some trouble making sure the 51% rule is met. I think they intentionally leave much of the non-critical issues like deburring just so that there is some visible work that will add up to 51% of the manufacturing rule for homebuilt experimentals.
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Have you see how much extra work we have to do compared to something like a Zenith? Or seen how insanely less work the RV-12 & RV-14 are than the early RV's we are building? We are probably doing 80% or the work here (on a slow build), not even close to 51%. Remember that Van's has so much extra % left in the old kits that they can sell a QB kit with HUGE sections of work already done.

If Van's re-optimized their old kits so that they do more of the machine-easy jobs (drilling to size, deburring, cnc-fab parts, etc) (like the new kits are) instead of leaving % for them to sell a QB kit, our time to completion could be cut significantly.
 
IIRC, the 51% rule is % of tasks; not % of hours.

One of the Cub clone companies now has a program where you can come to the factory & make the parts, and they finish the plane. Supposedly the FAA has signed off on it.

Charlie
 
rv7charlie said:
IIRC, the 51% rule is % of tasks; not % of hours.
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That's what I found also. So optimizing for the manufacturer to make the easy-to-machine, hard-to-human parts has a very large impact on time-to-completion. For example, having them final-cut the canopy (like in the RV-12) instead of having us do it (took me ~200hrs.)
 
https://www.eaa.org/en/eaa/aviation...ld-an-airplane/selection-articles/faa-51-rule

Looks like it's both the manufactur of parts plus assembly. I don't know how hours would be a relevant measure since that is going to be highly dependent upon the skill of the builder and the tools they have. It would be extremely subjective to go by hours, wherby measuring by the tasks makes more sense.

It may take be 4 hours to complete tasks A thru Z, but a more experienced builder with better tools could do it in 1 hour
 
On the edges, the main difference, I think, is that Van's uses a punch press that cuts edges like a fast sewing machine. This is very fast for making a lot of parts in a short period of time. The machine probably costs a fortune.

Having been to the Zenith factory, they use a CNC machine that drills the holes with a drill bit, and I believe they cut the edges with an end mill. This may be the difference.

My experience with water jet is that the edges are the opposite of "as if they were sanded". They have the courseness of sand. Maybe it is the shop I used, or the fact that they were cutting .063" or .090" aluminum.
 
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