Optimizing tooling and organization for prototyping

Having a tool changer is great, but 21 pockets doesn’t go that far when I need multiple sets of drills and taps (I’m just starting to experiment with combination drill/taps for some through holes). To give myself maximum flexibility, I’ve got basic end/face mills setup for steel and aluminum, and I’m leaving the rest of the space flexible for each job:

13D taster
2 1/8″ 3 flute finisher (Al)
3 1/4″ 3 flute finisher (Al)
4 1/2″ 3 flute rougher (Al)
5 2″ facemill (Al)
10 #3 center drill (Al or steel)
11 1/4″ chamfer mill (Al or steel)
181/8″ 4 flute finisher (steel)
191/4″ 4 flute finisher (steel)
201/2″ 4 flute rougher (steel)
213″ facemill (steel)

The center drill and chamfer mill are theoretically setup to minimize average tool change time, but since I cut mostly aluminum they probably don’t. I have mostly moved to drilling without center drilling first though, so that one at least is less critical.

The benefit of splitting these up along material lines is that if I need the space I can easily just pull all the holders for whatever material I’m not currently running. Theoretically I could pull the 3D taster most of the time as well, but I do use it fairly often so I haven’t gotten there yet.

The other factor in tool organization is what tools are permanently setup in their own tool holder, so I can set the offset and just switch them in as necessary (rather than have to remeasure, which is not that difficult but does add time). The biggest factor in that is cost, because it requires more tool holders, and I’m slowly adding to my collection as I get the opportunity.

I’ve found that SK16 collet holders are nice (low runout and lower torque required to seat than ER collets), and fairly inexpensive (a Maritool collet is ~$20, and Shars tool holders are ~$80). I have a previous post on my limited testing of Shars tool holders versus the Maritools here. The flexibility of a collet system is hard to argue with in a prototyping environment, although I know there are lots of people who would suggest heat shink or milling chucks (which are both out of my budget for now).

I have also discovered slitting saws and have been blown away by how effective they are for minimizing operations required for small parts. I was really surprised that they produce flat surfaces even when a very small web is left to hold up the part (I have been using 0.010″; in aluminum this snaps off with a couple bends).

I keep track of all of this using a Google Sheets document, so I can reference it on my computer in the shop and while programming in my office. I’ve made an example copy if you’re interested.

Turning a compressor tank into a fire pit

This tank came with my Quincy 325 compressor, which is now happily chugging away on a 60 gallon tank. I originally got it working on this tank, but I could tell that the inside was in bad shape and wasn’t sure the extent of the corrosion or health of the tank. To start with, I cut the tank in half with an angle grinder (and a whole pile of cutting discs). The wood shims were inserted to support the top as I cut around the tank, which ended up working great, and then I lifted the top off by strapping underneath the deck that the motor and compressor mounted to.

Turns out it’s very rusty in there. This tank wasn’t even that old, it was manufactured in 1993. Now, it might be that the serious pitting in the bottom wouldn’t have been an issue, but frankly the thing was bigger than I need and anxiety inducing enough that I didn’t want to keep it. If I’d payed anything like retail it would be a different story, but I payed around $450 including shipping for the entire compressor setup.

It takes a lot of cutoff wheels to get through this much steel.

‘Learning Experiences’ – crashes, broken tooling

This crash had a really neat outcome but a dead stupid root cause: I forgot to run the script that converts tool lengths from negative to positive. The tool ran into a piece of aluminum being used sacrificially under some thin polycarbonate, and impressively the drill survived. I didn’t stop the spindle as quickly as I should have, and it did a little orbital welding, which actually caused aluminum to flow up through the collet and into the collet nut.

A careless mistake: my first time using a slitting saw, and I had it on backwards (but spinning the right way). More orbital welding…

Lots of broken carbide: crashes from bad code, a loose vise, and a post processor that wasn’t setup for transitioning between multiple WCSs.

How I learned to check my coolant level regularly…after a few months the water does start to evaporate, and then you run out in the middle of a slitting cycle and the carbide explodes.