I've got a small moulder (20g approx.) manual ram type made by STP Ltd (now defunc company). I have not got a manual but I do have an example mould in Aluminium 6082. The example mould plattens are 4" square by 1.5" deep approx. Theres a fairly large tapered sprue (3mm) into a simple wheel like cavity.
I have a proxxon mini-mill type (BFW40-E) CNC machine which I've been working on and want to know what type of end mill and no. of fluts, I should be using? The proxxon spindle says it does 20K rpm and has collets in the range of 2mm to 6mm diameter (not larger enough for 1/4" tooling, will take 3/16" tooling fine).
I want to cut simple shapes into the mould cavity, circles for example. I read a few books on mould making but most literature covers large moulds, made from specially harded tool steel, made for real machines with bolters, ejector assemblies etc. But my moulder just isn't in that league. I mean the example mould is simply 2 plates of alu. with bakerlite handles attached so I can pull it out from the clamp. Oh, the clamp is manual screw type so I'd guess around 5ton max. going by other simlar machines on the web.
I would use a center-cutting tapered endmill made out of high strength steel. A carbide tool will keep a sharper edge but if you are too agressive with your feed and speed, the tool will snap. You want the endmill tapered to automatically put draft into whatever feature you are adding into the mold. Hope this helped
use as less as possible no of flutes, if u can found an Al router, its contain only one flute. Bcoz Al chips need more space, use soluble cutting oil or kerosene for cutting lubricant.u can get more miror like finish with this machine. u also can successfully use two flute ball nose end mill of size 4 or what u like on running more than 15k rpm and 2500~3000mm/min feed rate.