Looking for advice for programming and running a CNC mill department

I was hired to work along side and eventually replace an out-sourced programmer that programs our (1) haas vf2ss mill. The owner has given me the responsibility of taking over their new mill department due to no one else having experience or not wanting the stress. This place has transitioned from a screw-machine shop to an all CNC swiss lathe shop + a haas mill. I had experience in setting up Swiss lathes and a bit of experience setting up mori mills and a ycm. My only experience programming on the field was at my last spot it was a mold shop and I'm finishing up my last mastercam class at community college.

I got some general questions, I don't want to get into too much detail or ask for industry secrets.

-I want to know if it is best to program my parts from the center as opposed to a corner?

-I also wanted to know what type of work-holding is used in production shops or than vises?

-I'm considering asking the owner if we could switch to Mastercam for our milling and euro-tech lathes.

The jobs coming are extremely simple dimensionally. The general manager purchased Paws work holding fixtures from the guys in Michigan. I'm nervous about jumping into these fixtures because I haven't yet explored how to program them or what reference point to use if I take these fixture/jaws on and off the table. I'm not sure if software plays a big factor with our capabilities with fixtures. They use Esprit, actually everyone programs manually and no one uses the software. Any tips or things to think about would be appreciated.

Yes, having the work offset at the center of stock is better. Your stock won't be exactly the size you programmed for, and programming from center evenly distributes any size difference around the part. This means if it's over, you don't have your tool hitting a ton of material on one side, and if it's under, but still big enough for the part, it will clean up all around. I'll often put Z0 at either the top of stock, top of finished part, or top of the vise jaws if I'm planning on cutting really close to them. Does the machine have probing? That saves a ton of time and reduces errors.

Most used workholding for me is a vise with serrated step jaws, a vise with soft jaws to machine to hold the part for the flip side, and sometimes a vacuum plate:
SmartVac 3 Vacuum System – Pierson Workholding

Also occasionally a collet block.

I've been using Mastercam since '95. While it's pretty good for milling up through 5 axis, and fine for live-tool lathe, it's very weak for Swiss and millturn.

mhajicek said:

Yes, having the work offset at the center of stock is better. Your stock won't be exactly the size you programmed for, and programming from center evenly distributes any size difference around the part. This means if it's over, you don't have your tool hitting a ton of material on one side, and if it's under, but still big enough for the part, it will clean up all around. I'll often put Z0 at either the top of stock, top of finished part, or top of the vise jaws if I'm planning on cutting really close to them. Does the machine have probing? That saves a ton of time and reduces errors.

Most used workholding for me is a vise with serrated step jaws, a vise with soft jaws to machine to hold the part for the flip side, and sometimes a vacuum plate:
SmartVac 3 Vacuum System – Pierson Workholding

Also occasionally a collet block.

I've been using Mastercam since '95. While it's pretty good for milling up through 5 axis, and fine for live-tool lathe, it's very weak for Swiss and millturn.

Click to expand...

That was my idea exactly and you can pick up the center back. It does have probing with the renishaw toolsetter and the spindle probe. i've learned how to play with some of the setting for work offsets. there seems like a lot of potential with the probe.

georgee1 said:

-I want to know if it is best to program my parts from the center as opposed to a corner?

-I also wanted to know what type of work-holding is used in production shops or than vises?

-I'm considering asking the owner if we could switch to Mastercam for our milling and euro-tech lathes.

Click to expand...

@mhajicek mentions programming from center already and the reasons why it can be beneficial. This is pretty common for 1st op when starting with the raw material. Once you flip the part, you'll need to locate the part off of a machined surface. For 2nd op, I try to locate off of a datum or at least set my work coordinate to one. I feel it's a bit more useful to do that because adjusting directly to the datum rather than compensating multiple tools is much more straight forward and you don't end up chasing your tail around.

I haven't used PAWS specifically, but have used similar tooling in higher production environments. The things you want to take note of is whether you will need to make an offest for each fixture/part location, or use a single global offset. The former is a bit more to setup, but if you're running tighter tolerance parts, you can adjust each work offset individually. You can also incorporate work offset setting with a probe into your program if you need to dial in each part.

Other work holding can be pretty wide ranging. Some shops use custom form vise jaws for every job which are relatively easy to design and make, or entire fixture plates which can take a lot of time to design and make. Vacuum fixutres, dovetails, mitee bites, whatever works well and has the potential to be used with other parts. Try not to get over zealous, and stay practical. Simple solutions tend to work the best, but not always. One piece of advice with any custom fixturing you make, take your time to make it perfect dimensionally. A well built/cut fixture will lead to less bad parts, and if you have to use it again and again, then you're doing yourself a favor. Nothing like fighting a crap fixture over multiple part runs only to finally recut or dial it in on the last.

As for CAM, maybe ask to have them pay for training on their current system first. But it's up to you. CAM isn't cheap and production shops usually don't like to spend money. Though, if you're proficient with MC, then it may just pay for itself...