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Example of a Very Good Assembly Jig

David Paule

Well Known Member
This is a very good example of a good building jig. Here?s why:

1. It rotates to any convenient position.

2. It?s stiff enough to hold everything in alignment without excessive sag.

3. It?s open for access to the hardware.

4. The jig?s frame is spaced far enough away from the device itself that tools can be used between the device and the jig. And the main frame of the jig is out at the corners of the thing inside it.

4. The device?s supports, that hold it to the jig, are relatively unobtrusive.

FuK48UB.jpg


I got this out of the Wall Street Journal. Sorry for a photo of the page rather than a screenshot. The jig is one of Boeing's but I don't know what the thing is that they're building.

Dave
 
At Airbus, the floor would be raised to eliminate the fall-risk of the steps. Just sayin?! The manufacturing fixtures are as big a development as the plane itself. Really impressive.
 
Large amount of tooling and fixtures is on the way out in aerospace due to large capital investments required and inability to scale with production rates changes. This along with desire to increase quality and reduce touch labor will be eliminating subassembly fixtures like shown in the picture. Perfect example is Vans prepunched kits. Less fixtures, less labor, faster builds. Big aerospace is catching up to the homebuilt market.
 
Large amount of tooling and fixtures is on the way out in aerospace due to large capital investments required and inability to scale with production rates changes. This along with desire to increase quality and reduce touch labor will be eliminating subassembly fixtures like shown in the picture. Perfect example is Vans prepunched kits. Less fixtures, less labor, faster builds. Big aerospace is catching up to the homebuilt market.

This is not an accurate statement. Boeing has been able to scale production rates on the 737 from 30/month to over 50/month over the last several years. They are going to up the rate to over 60/month soon. They do this while still using large assembly jigs.

Assembly of a large airplane and a small airplane are different animals. For example, it's easy to build an RV wing without a jig is relatively easy for two reasons. Yes, pre-punched kits are a major improvement, but it's also much smaller than a 737 wing. Can you imagine trying to rivet together a 737 wing on a large table? Assembly jigs are necessary at this scale.

Tolerance stack-up on a large scale will kill you without a jig. It's less of a problem on an RV precisely because it doesn't have room to accumulate. Imagine the vertical and horizontal stabilizers having a four to six inch length difference as measured from the nose between different planes. Flying characteristics would vary from plane to plane.

Here's one way Boeing reduces labor hours. Instead of drilling each hole individually, in some cases such as along the fuselage laps splices they've invested in a specialized multi-hole drill. The lap splices are three rows of holes drilled through the two overlapping skins. Literally hundreds of holes are drilled simultaneously with great precision and quality.
 
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The intent of my posting was to provide some ideas for the people who, like me, are building a non-prepunched kit.

I've just finished up using a steel Fry jig for the fuselage of my RV-3B, and it sold in one day. In that time period, I had a backup buyer, too, in case the first failed to complete the deal. He did not fail. This should give you an idea of the demand for a good jig for us homebuilders these days.

Although the example was from Boeing, it's lessons are very applicable to us.

Dave
RV-3B, fuselage now a canoe.
 
Assembly of a large airplane and a small airplane are different animals. For example, it's easy to build an RV wing without a jig is relatively easy for two reasons. Yes, pre-punched kits are a major improvement, but it's also much smaller than a 737 wing. Can you imagine trying to rivet together a 737 wing on a large table? Assembly jigs are necessary at this scale.

Tolerance stack-up on a large scale will kill you without a jig. It's less of a problem on an RV precisely because it doesn't have room to accumulate. Imagine the vertical and horizontal stabilizers having a four to six inch length difference as measured from the nose between different planes. Flying characteristics would vary from plane to plane.

https://patents.google.com/patent/US6808143B2/en
https://pdfs.semanticscholar.org/3a06/aa5a5a0edaecf08a52d9fe020b09ebc63ba2.pdf
 
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