martin_05
Hot Rolled
- Joined
- Mar 11, 2009
- Location
- Valencia, CA, USA
Just got an email from Protolabs that led to this link:
Design Tip: 6 ways to optimize part design for CNC machining
I wonder what your opinion might be on the question of not drilling, but rather interpolating every single hole and avoiding taps in favor of thread milling.
My first reaction was that cycle time and machine wear and tear would be increased. And then I realized this is Protolabs, a high volume operation. If this works for them, why wouldn't it work for everyone else?
One of the other questions that popped into my head was: Do they also plunge entry into every hole they interpolate or do something else (spiral, etc.)?
I can't see that thread milling for standard thread sizes can possibly compete with the cycle time of rigid tapping. Yes, you'd have to load the appropriate tool, etc. Maybe they've optimized their workflow so that a standard set of tools in the tool changer can handle 90% of what they get and they reserve, say, 5 tool positions for exceptions?
We are not a production shop but it would sure be nice to simplify our prototype manufacturing to avoid having to setup a bunch of tools for every job. We have that to some extent but we still use drills and form taps. Our standard tool set looks something like this:
VF2 with 20 position umbrella tool changer.
01 2 in diameter carbide insert shell mill
02 1/2 in 90 degree spot drill
03 Drill chuck
04 Drill chuck
05 Tap
06 Tap
07 1/8 in carbide end mill
08 3/8 in carbide end mill
09 1/2 in carbide end mill
10 3/4 in 4 inch long carbide end mill
11 #3 82 degree center drill
12 #6 82 degree center drill
13 1/4 in carbide ball end mill
14 3/8 in carbide ball end mill
15 Engraver
16 Open
17 Open
18 Open
19 Open
20 Renishaw Probe
I tend to use the same tools (always the largest possible) for roughing and finishing. Again, not a production shop so dedicated roughers don't seem to make sense. I have a couple of 1/2 in roughers but never seem to use them. I'd be interested in opinion on whether or not this is a good approach.
Finally, later in that article they say:
"With parts larger than 10 in. by 7 in. (254mm by 178mm), only the top and bottom can be machined: no side setups!"
I wonder why that is? Is it because of their process? What are they doing? Or is it the limitations of their machines (xyz envelope) or work-holding approach?
Thanks.
Design Tip: 6 ways to optimize part design for CNC machining
I wonder what your opinion might be on the question of not drilling, but rather interpolating every single hole and avoiding taps in favor of thread milling.
My first reaction was that cycle time and machine wear and tear would be increased. And then I realized this is Protolabs, a high volume operation. If this works for them, why wouldn't it work for everyone else?
One of the other questions that popped into my head was: Do they also plunge entry into every hole they interpolate or do something else (spiral, etc.)?
I can't see that thread milling for standard thread sizes can possibly compete with the cycle time of rigid tapping. Yes, you'd have to load the appropriate tool, etc. Maybe they've optimized their workflow so that a standard set of tools in the tool changer can handle 90% of what they get and they reserve, say, 5 tool positions for exceptions?
We are not a production shop but it would sure be nice to simplify our prototype manufacturing to avoid having to setup a bunch of tools for every job. We have that to some extent but we still use drills and form taps. Our standard tool set looks something like this:
VF2 with 20 position umbrella tool changer.
01 2 in diameter carbide insert shell mill
02 1/2 in 90 degree spot drill
03 Drill chuck
04 Drill chuck
05 Tap
06 Tap
07 1/8 in carbide end mill
08 3/8 in carbide end mill
09 1/2 in carbide end mill
10 3/4 in 4 inch long carbide end mill
11 #3 82 degree center drill
12 #6 82 degree center drill
13 1/4 in carbide ball end mill
14 3/8 in carbide ball end mill
15 Engraver
16 Open
17 Open
18 Open
19 Open
20 Renishaw Probe
I tend to use the same tools (always the largest possible) for roughing and finishing. Again, not a production shop so dedicated roughers don't seem to make sense. I have a couple of 1/2 in roughers but never seem to use them. I'd be interested in opinion on whether or not this is a good approach.
Finally, later in that article they say:
"With parts larger than 10 in. by 7 in. (254mm by 178mm), only the top and bottom can be machined: no side setups!"
I wonder why that is? Is it because of their process? What are they doing? Or is it the limitations of their machines (xyz envelope) or work-holding approach?
Thanks.