Scanning a casting

Not sure if this is the right section, but as bits for steam locomotives are being cast, I thought I'd try here.

We have a casting that we would like to scan in 3D, so that we have a digital copy of it in case we want to make another. Can anyone give us some tips how to get this done? Is there a laser gadget on a tripod that one can borrow, or a company that will come and do a full scan for us?

 

My employers have had contract laser scanning jobs done by Hexagon, who distribute all the Leica 3D trackers and scanners (https://www.hexagonmi.com/en-GB/service-and-support/measurement-services/contract-inspection). I can't tell you how much it cost, because I wasn't involved in that particular job, but the portable laser scanning kit is Really Not Cheap; the handheld laser scanner is used in conjunction with an AT960 laser tracker, which is £100k+ on its own. Other service providers using that or other kit are almost certainly available, but that's one I know can provide the sort of service you're asking for.

One piece of advice, make sure you know what you want in terms of the CAD file before placing the contract and get somebody to examine the file as soon as you get it in. I will always suggest requesting a STEP file if remotely possible, any decent 3D package will open them and in my experience they cause less trouble than IGES or STL, but whatever format works for you is fine.

 

If you search for 3D scanning services there's quite a few companies that pop up that can handle a range of sizes and resolution. As @8126 says, it's not a tool you buy - yet! I've no idea what prices are like, but a search came up with this company, looks like you can either take something to them in Bristol, or they can come to you, and they've a range of scanners presumably with different resolution and associated cost. If you look at their "case studies > heritage" tab I guess that's the sort of service you have in mind? What's the casting out of interest - you always seem to have a fair few "in the offing" so to speak!

 

The A1/P2 people had some scanning done recently: https://www.p2steam.com/wp-content/uploads/2018/09/MM-47.pdf

 

I can't find the reference to scanning in it though?

 

I don't believe it was laser scanning, from those pictures, and it's not really the right application, since I guess they were measuring up the hornguide surfaces. They'll have been using a laser tracker to establish (quite a few) accurate points, then inferring surfaces from those points, whereas a laser scanner will give you a much bigger cloud of (less accurate) points, which is ideal for recording a casting with lots of radii and fillets. The thing with the laser scanners is you need to know accurately where they are, so either they're on some sort of co-ordinate measurement machine, whether that be a gantry or articulated arm, or you track the position of the (handheld) scanner with a laser tracker or something like it. The correct kit depends on how big and how mobile the thing you wish to scan is.

As a slight modification to what @flying scotsman123 suggests, a quick internet search for reverse engineering services in your area may bring up some useful leads; it avoids being too prescriptive about exactly what technology you want to use.

 

The casting will also be a different size from the pattern which will need taking into consideration.