Hi @MarkRausa to be honest, you’re asking a lot for a total budget of £3k, so I’d be inclined (for now) to split the problem down into what you need to do and what can be done by others (services). You’re the health professional, so you need to be involved in the modelling of the casts/splints, but you really don’t need to be involved in the actual printing at this stage. 3D printing, especially in specific materials, is a relatively complex task and, at least in the early stages, I believe you should concentrate on producing your digital model, then let a 3D printing professional worry about how it’s actually going to be made.
So, you’ll need a 3D scanner and some software. The scanning part is surprisingly difficult. There are lots of 3D scanners out there, although we can (I think) ignore those that are turntable based/fixed (unless you’re going to chop off the arm/leg to scan it). Handheld scanners start right down at £100 or so and go all the way up to crazy prices (Artec Eva - a snip at €13,700). At this stage, I’d start at the cheap end, perhaps with the Cubify Sense - £400 or even the Kinect version, although that does require more fiddling. I’d start here because even once you’ve got a scan, you’re going to need to do a lot of work in making the actual model. You’ll need to learn how to clean the scan and then how to turn that scan into a voronoid cast such as those you’ve mentioned. The good thing is you don’t need ultra-detail, an arm (or leg or ankle) is really a pretty simple shape (in 3D printing/scanning terms compared to a face or a whole body).
Software wise there are quite a few free apps out there that’ll work well for you. Autodesk Meshmixer is a great tool for simple modelling like this (and their home page actually shows prosthetics and casts, which must be a good sign) and it does voronoid stuff really quite easily. Something like Sculptris might work well.
If you’re insistent on getting a printer, then FDM is going to be a tough ask. Although not ultra detailed, these models are complex and full of holes, two things that FDM really doesn’t like. I can be about 95% certain that all the images associated with the two types you mentioned (Osteoid and Cortex) are not FDM printed parts - they’re way too smooth, so they’re either SLA, DJI or SLS and any way you cut it, £3k ain’t gonna get you that technology at the sort of sizes you might need, so again, I’d say focus on getting yourself a good digital model you’re happy with, upload it here to 3DHubs and get someone (I can’t possibly suggest who) to advise on printing it. Money spent on getting the prints done professionally will save you money in the long run as you’ll have time and money to develop the design end, making sure the products are fit for purpose, rather than having £3k worth of printer sitting there wasted because you never were actually able to produce a digital model.