[dent424]

Hi,
I'm fairly new to milling, but I've been trying to get more value out of the CNC machine in my shop. This is going to be a really basic question. Here's a quick rundown of my situation. My shop is fairly behind technologically, and I'm trying to get it up to snuff. One of the things that I'm really interested in is getting the person operating the new Mori Seiki machining center in the shop to use more aggressive feeds and speeds when appropriate. Right now he generally just runs the thing with a 50mm/min feed no matter what end mill he's using for any purpose, which I know is not the right thing to do in all situations. When I look at the power usage bar on the machine's screen during milling (or any other operation for that matter), it rarely goes above 10 or 15% except in some corners sometimes. It just seems like the machine could do a lot more.

One of the concerns that he expresses is that he's going to wear out the machine. My question is, "How valid a concern is that?" What are the factors that go into wearing out a CNC machine, and what is being "Too Aggressive" with a machine? Obviously I don't want to be breaking end mills or forcing emergency stops, but beyond that, is there going to be significant damage if I'm pushing the machine harder?

Thanks for your help!

[moriboy1]

Like anything mechanical, the harder you push it the sooner something is going to break. But, good machines like your Mori are designed to be pushed a little and still hold up. In our shop we see a lot more electrical issues as the years go by vs mechanical problems. The electronics foul up no matter how easy or hard we run them.

[wizard]

Hi,
I'm fairly new to milling, but I've been trying to get more value out of the CNC machine in my shop. This is going to be a really basic question. Here's a quick rundown of my situation. My shop is fairly behind technologically, and I'm trying to get it up to snuff. One of the things that I'm really interested in is getting the person operating the new Mori Seiki machining center in the shop to use more aggressive feeds and speeds when appropriate.

If he isn't oriented to being productive why is he still with you?

Right now he generally just runs the thing with a 50mm/min feed no matter what end mill he's using for any purpose, which I know is not the right thing to do in all situations. When I look at the power usage bar on the machine's screen during milling (or any other operation for that matter), it rarely goes above 10 or 15% except in some corners sometimes. It just seems like the machine could do a lot more.

Probably. You won't max out a machine with every operation you do, it some cases it is silly to try too. What you should strive for is maximum utilization of the tools used for each operation. A good speeds and feeds calculator will help here.

One of the concerns that he expresses is that he's going to wear out the machine.

To which your response should have been baloney or something stickier. Sure hard milling will wear a machine but this fellow seems to be at the opposite end of the spectrum. Oh and by the way not using tooling correctly can lead to short lifetimes on your cutters.

My question is, "How valid a concern is that?" What are the factors that go into wearing out a CNC machine, and what is being "Too Aggressive" with a machine?

Obviously I don't want to be breaking end mills or forcing emergency stops, but beyond that, is there going to be significant damage if I'm pushing the machine harder?

Too aggressive breaks things. In your case though you have a long ways to go before you utilize all of the machines capabilities. It is completely possible that you will break some end mills before you reach ideal parameters. That can be minimized with some research and the above mentioned speeds and feeds calculators. When it is all said and done each tool should run its own feed rate and depth of cut.

Thanks for your help!

It think you either need to have a long sit down talk with your machinist or post adds for a replacement. There may be legitimate reasons for his feed rates but I just have a feeling he defaults to a value he is happy pay with. Since you have a good machine here, one that can run for years in production, I'd want to know that it is being as productive as it can be. So unless there is a rational argument against faster machining speeds I think a change in attitudes is in order with your machinist. By the way materials are critical here for many alloys you have no choice but to go slow.

Look at it this way, if you cut production time in half without impacting cutter wear out you will save huge on production costs. You don't even need to cut things in half even a few points better can impact profitability.

[dent424]

Thanks for your response! The problem with the machinist (and my shop in general) is a complete lack of education. My shop is located in Japan and the very odd thing about this country is that, despite it's image, in many areas it is extremely backward. For every Fanuc or Toyota, there is a shop like mine where most people have no idea how to use computers, have no idea that HSM exists, and carry on using a CNC machine like a manual machine (in terms of feeds and speeds). In addition, it's hard to find vendors that will make good recommendations.

Since I got here 2 years ago, education has become a big priority, and I have been gradually pushing to get people more educated. The good news is that, with this machinist in particular, he's actually quite sharp and willing to learn. I just need to allay some worries that he has heard (from other, more experienced machinists in the shop unfortunately). He has already put some things in practice, and I have gradually been able to raise his productivity. Since until recently I didn't have any knowledge of feeds and speeds either, I couldn't say much to him about it, but now that I've done some studying, I'm hoping that I can work with him to improve his productivity.

Anyhow, thanks for the advice. I really appreciate it.

[underthetire]

What model Mori?
With look ahead turned on, and all the newer machines have it, you won't cause any significant wear. What is hard on machines is the rapid corners when feeding high, above 200ipm. The look ahead function in the moris will calculate optimal corner speeds, so you won't have that clunk or pop you hear on some machines. 50mm/m is terribly slow, you should be able to do some operations 10x that speed or more, depending on type of material and max spindle speed. The thing that kills machines faster than anything but crashes, is lack of maintenance. Coolant drains plug up, chips pack under covers, pretty soon your replacing thrust bearings.

Your mori is designed for much faster speeds than you are using. So is all modern tooling.

[rlockwood]

If you push a mori hard enough to wear it out, I'd imagine you will have paid for a couple new mori's along the way.

[LeeWay]

Not only what has been mentioned already, but going that slow for most tooling will kill the tools life. That means they won't last nearly as long. You are not only paying for much longer machining times and wages for that, but also higher tool costs because of premature tool wear.
Even in a small shop, it is economical to machine the correct way when possible.

I just invested in Gwizard. I built a small mill maybe 5 years ago and have been using it without any feeds and speeds charts. I found out what worked and what didn't and stuck with that.
I also have a larger machine now, so invested in GW after the trial was over.
What I did find out was that what I had been using on my home made mill for feeds and speeds of various tools was very close to what Gwizard recommends for that very same application. That is why I invested in it really.

[rhost]

50mm/m is a little under 2in/min. A hobby mill could go faster.

Sent from my SGH-I777 using Tapatalk 2

[jimglass]

The speeds and feeds for manual machines are the same as CNC so keep that in mind. The load meter on your machine only shows the electrical current used by the spindle motor. The load meter will register increased loads with large endmills taking heavy cuts where pure horse power is required.

There are simple formulas for calculating speeds and feeds. Once you know how to make these calculations you can check your operators settings to see if the machine is running at optimum. If the operator is machining the same material with the same size tools the machine will appear to be running the same speeds all the time.

Running proper feeds and speeds is not likely to wear out a machine prematurely. Running large tools and taking heavy cuts could be a different story. The worst thing for any machine is to run it without proper lubrication.
Jim

[dent424]

Thanks for your responses everyone! I really appreciate it. I have indeed recently invested in a copy of Gwizard which I love. It will definitely make a huge difference, and I hope to be using it much more often!