A while ago, I asked for some help on here on developing a scalloped surface. Here is the link to that thread. I went on to use that texture in a 3d model I rendered. The entry courtyard is enclosed in metal panels with an over-sized scalloped surface that was developed in Grasshopper. You can see them with a white finished on either side.
How was the scalloped surface done on the metal panel? I take it the surface isn’t metal, or is light gauge stamped of some sort?
I was thinking it could be cnc routed out of a soft metal like aluminum.
Routing foam would give you more economical options. Either as a mold or inserted into a metal back pan.
Definitely! CNC’ing from an aluminum blank that large would yield a lot of waste. Do you know a good means of coating a piece of foam such as the one you linked to allow it to be weather resistant?
I work with metal panels so not familiar with foam coating options, but thinking there are a lot, depending on the edge quality you are looking for.
Something like the method shown here would be good for mass production.
Have a look at Valchromat panels. These are often used for machining 3d texture patterns. The panels can be waterproofed with the right coating I believe.
Valchromat is supposed to be very nice to machine and has good environmental credentials.
Pros and Cons of Valchromat
I think you may have to compromise to some extent, whatever material you use, in that you will have machining marks in the finished surface depending on the diameter of cutter you use to machine the surface and the “step over” of the toolpath. Step over is the amount of the diameter of cutter that overlaps on each pass. The smaller the step over, the smaller the final tool marks will be on the surface but the longer it will take to machine and the more expensive it will be. The machining marks can look good though… kind of like contour lines.
If you are set on aluminium one way to help reduce the cost would be too split the panels into tiles and machine each tile. If you try and find someone with a CNC capable of machining aluminium and large enough to machine, for example, 2.4m x 1.2m panels (a standard size of sheet materials) then it will probably have a high hourly rate. CNC machines with smaller bed sizes are more common.
It is possible to get some materials electroplated in a metallic finish. Again, machining smaller tiles would be better suited for this. I’m not sure what base materials can be electroplated but this service seems to have become more available since the rise of 3d printing so I presume non-metallic materials can be electroplated.
Personally, i would go for Valchromat or a similar PU board if you don’t mind plastics.
Hmm I’ve been milling quite some Valchromat for indoor applications but wouldn’t use it outdoors. In their tech sheet they also don’t recommend any outdoor applications:
You’d need a very strong waterproof coating and even then I’m not sure how it will work over time. One tiny scratch that’s too deep and the piece gets ruined.
I’d go for making a positive in foam, then making a silicone mold out of that and then casting it in some kind of reinforced concrete.
After browsing through the Valchromat website I’d agree with you… I’m sure there’s a way to waterproof it especially if it is not likely to experience much wear and tear.
I’m interested in seeing how it machines… Any tips for spindle speeds, feedrates and depth of cut?
I wonder if milling a mold, (foam, high resolution), and making a mold from the milled bit, then casting as some lightweight concrete might be a solution?
(scale of project may be a bit different than this link, but this type of approach)
I’ve never machined the stuff before, but Corian might be able to do the job?
It mills indeed pretty nice, as you say.
For 2D-cutting: with a 6 mm diameter single-flute upcut milling bit I usually run it at 18000 rpm, feedrate 40mm/sec and cutting in one go through 19 mm thickness. It’s certainly possible to go faster but it will affect your finish quality rather soon unless you change to a bigger milling bit or with more flutes.
For 3D-milling I don’t have exact numbers in my head, since I do it a less often but using the numbers above and going a bit less deep should work. I can’t remember if I’ve ever broken a bit on Valchromat.
But with 3D-milling surfaces like this you’ll also experience warping, similar to mdf. The Valchromat is not as consistent in density on the top and bottom surfaces as it is in the middle. So if you mill away one side you also take the tension away on that side causing it to warp. You could decrease this effect by milling away a layer on the other side as well, but I’ve only heard about people doing that.
I have done this with high density foam then casted in plaster, my next step is to try to cast with fine concrete , so i think it can be a solution
zinc is a soft metal which was often used in the 19th century architectures, e.g. New York and Chicago building and their ornaments.
attached two samples of stamped zinc. The bull eye is made of natura zinc and the stamped tiles is preweathered.
need more send, send questions to firstname.lastname@example.org
The bulls eye looks more like it was cast not stamped.
Looking at your texture, it is a typical forged surface and if you want a long lasting material then I would forge 16 guage stainless…the finish can be matt, satin, polished or heat coloured.
The bulls eye looks more like it was cast not stamped.
The main parts of the roof windows was mechanical curved and leaf are stamped and soldered.
To produce the leaf, they use a cast moulder to stamp it.