European vs North American Manufacturing Methods

[GeorgeRa]

Originally Posted by booster

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That said, a lot could be done to improve quality and efficiency in the current methods of building, I am sure. The standard consultant line when they are trying to sell management their services was that they could save 30% of the cost of production not including materials. Obviously, this was BS as they hadn't analyzed the processes at that point, but on average it might be close with some being less and some being more. In RV building, I don't think that the large volume builders would get quite that much in cost reduction, but they probably could reduce defects much more than that. As was mentioned, quality ain't free, but it can also also very easily be an overall cost improvement if done right. Warranty work is very expensive in both dollars and reputation.

Agree, there is a gray scale between automotive level of automation and hand crafting. RV manufacturing in NA is at the craft end of this spectrum.

I remember looking at Airstream Interstate before venturing into our DIY. The joint between cab headliner (MB) and Airstream ceiling required a multi curvature interface. I don’t remember exactly how Airstream did it but I remember it didn’t look good, not good enough for an expensive camper van. A perfect application for a snaped-in molded plastic with added insulation instead of mickeymoused something from plywood and fabric. It would require a good design and expensive mold, but this part could be leverage for all Sprinter conversions at Airstream. This is just one example of investing toward better quality of fit and finish.

[booster]

Originally Posted by GeorgeRa

For my build practically all aluminum framing from 80/20 was cut at the factory from my CAD drawings. I didn’t have access to laser scanner but to fit overhead cabinets side and inner walls to the curved MB headliner I scan its curvature with my venerable Leica D330 setup manually (angle/distance) with a 3/8” resolution then sent it to CNC.

I don't know if ARV scanned the Spinters or used the factory fitter drawings that, I think, are available to reputable fitters but they do fit everything ahead of time and CNC them out IIRC. I am sure davydd will tell us for sure.

[GeorgeRa]

Originally Posted by booster

I don't know if ARV scanned the Spinters or used the factory fitter drawings that, I think, are available to reputable fitters but they do fit everything ahead of time and CNC them out IIRC. I am sure davydd will tell us for sure.

I had access to Sprinter 3D scans for cargo vans. I needed the headliner 3D scan which was not available from MB. Mounting overhead cabinets with headliner in place is not very common, I know just a few fellows from the Sprinter Forum and they more or less just copied my method.

[booster]

Originally Posted by GeorgeRa

I had access to Sprinter 3D scans for cargo vans. I needed the headliner 3D scan which was not available from MB. Mounting overhead cabinets with headliner in place is not very common, I know just a few fellows from the Sprinter Forum and they more or less just copied my method.

I was just wondering because the 3/8" accuracy is not very good.


I think you could get to much better than that with a story pole and a level with a 12" scale taped to it.

[avanti]

Also, don't overestimate the build precision of large vehicles--especially body parts. The CAD files you get from the OEM are "as designed". "As built" is a different matter. I suspect that this varies by manufacturer--one might assume the MB is better than most along this dimension. But if you need real precision, you may need to measure your instance.

[Davydd]

Originally Posted by Punkinhead

I know Ford provides 3D CAD models of the interior of the Transit so I'd be surprised if Promaster and Sprinter didn't also.

Mercedes Benz provides complete 3D CAD drawings to upfitters. Advanced RV uses them with Solidworks 3D. I never saw my drawings for Mies from ARV and they claimed they didn't need them and built off my drawings. Maybe they did because the dimensions were extremely accurate and true to my drawings for 2D. For 3D I took to more conceptualizing and artistic license.

I'm still trying to figure out what I could have done better now that I am using my van but still have trouble to modify it as much as 1 inch and have it meet my criteria.

I used resized raster drawings for an underlay to design my van and surprisingly they were pretty accurate. My CAD tools were SketchUp 3D and Microspot MacDraft 2D which is a WYSIWYG (What You See Is What You Get) application which emulates hand drafting while you work.

We used Bentley Systems CAD software to design/build the 5 billion dollar Mall of America and subsequently when I moved on to Target Stores. I have no idea what Target uses today as I have been retired 16 years. Bentley has changed considerably.

In the 80's when I had my own architectural firm I taught at the University of Minnesota a class called "The Electric Architect" or all things computer including 2D and 3D CAD mostly to architectural firm owners, who where very skeptical of this computer trend.

[Davydd]

Originally Posted by booster

It would be nice but it won't happen.

You are right. The RV industry especially with Class Bs which you have to build in an existing shell after the shell is built can't justify the billions of dollars to do so. The auto industry in America is 5.8 million units on the average. What are the builds for Thor and Winnebago? If it was even attempted you would have fewer choices and models in what you can get in a Class B.

I was just texting with a friend who was considering buying a Grech Turismo, the 20 ft. long Sprinter, but the dealer couldn't satisfy his wants and modifications so he passed on it.

[GeorgeRa]

Originally Posted by booster

I was just wondering because the 3/8" accuracy is not very good.


I think you could get to much better than that with a story pole and a level with a 12" scale taped to it.

I have Leica D330 and tripod adapter LSA360 and used it extensively during conversion. One of the most useful tools I have. I mark the profile to be measured with blue tape and take measurements of distance and angle about 3/8” apart. Transfer the data to CAD and run a curve fit. Kind off poor man 2D scanner.

I didn’t say it correctly, the resolution of data points was about 3/8”, actual measurement was based on angle and distance measurement accuracy, +/- 1mm and +/- 0.3 degree. So, 3/8 distance between data point was my choice as I needed to take the data manually.

I wish to have a 2D scanner instead, but they are unjustifiably expensive for my needs.

EDIT My Leica D330 which I purchased long time ago went kaput a few weeks ago, sometimes it works sometimes it become nonresponsive. When I bought Leica, this was the only type of tool on the market, since there are more of them and much less expensive. If you are interested using laser distance measurements I just bought this one https://www.amazon.com/dp/B0BLNT9V4H...roduct_details, specs are not as good but sufficient for much less money.

[avanti]

If you haven't been keeping up on what a modern iPhone can do with its built-in LIDAR, check this out:

https://poly.cam/capture/4F9946EC-B8...B-0D7963E1D7E2

It is a scan of the underbody of a guy's Transit that he made with his phone.

[the image comes up with an "above" view, which isn't very interesting. Flip it over with your pointer.]

This may or may not be good enough for any given purpose, but this is all moving forward very fast. It was certainly very useful to me for positioning tanks, etc.

[GeorgeRa]

Originally Posted by avanti

Also, don't overestimate the build precision of large vehicles--especially body parts. The CAD files you get from the OEM are "as designed". "As built" is a different matter. I suspect that this varies by manufacturer--one might assume the MB is better than most along this dimension. But if you need real precision, you may need to measure your instance.

Except the overhead cabinets I mount all other cabinet/modules primarily to the floor. CAD dimensions between the threaded holes on the floor were very accurately corresponding to laser gauge measurement reality. I think MB CAD dimension are very accurate within stamped parts, but chassis is not rigid, it flexes in some places a lot and measurements in situ are necessary.