What are the rough dimensions of the spline and the part? This has quite a bearing on your options to have the parts reproduced. If they are small enough, rotary broaching may even be an option for you. This way you can just take it to a local shop.
Spline Broach Form...
Slater Tools most often recommends our standard M2 broach cutting tools for low carbon steel. These are hardened to the max. at heat treat, and ground to size. However, this is only for a rotary broaching application. If you are trying to chose tools before machining, check with the shop guys...
Machining the hex head in medical stainless steel bone screws is often done with rotary broaching. See some folks who do it at the bottom of the page at: http://www.rotarybroaching.com
The hex (or another shape) can be formed in your aluminum parts easily using rotary broaching. The rotary broaching toolholder can be set-up in any CNC machine so you should have no problem putting it into your part. The broaches for this tooling are quickly delivered (available in 1-2 days)...
Most bone screw products seem to designate hex or torx type (hexalobular) driving features. These can be made with common CNC tooling.(see http://www.slatertools.com/adjustment_free_rotary_broach_toolholder.htm)
What other driving features are recommended for orthopaedic bone screws?
Most of the rotary broaches we make for security solutions are a hexalobular form or custom form the customer specs for his fasteners. We make the broach, internal or external, and they use it with the holder to produces 100's or 1000's of fasteners which use that form. The picture from the...
Please excuse this comment if I make a rookie observation here. I do not know how large the plates are which are being laser cut. Is the part small enough to be put on a lathe as a second operation. Perhaps a rotary broach tool would be able to cut the square? Of course, this depends on how...
You may want to check out rotary broaching for involute splines. If you plan ahead in design this can be a great time and money saver during production. Rotary broaching can accomplish internal and external splines. See the video at slatertools.com
