Setting tool height

[is300driver]

This is a pretty simple question: Out of all the methods for setting your z depth, which is the most accurate in your opinion? And, how are those electronic tool offset guages suposed to work?

thanks, alex.

[ajl6549]

We use a tool presetter made by Royal it has a certifide gage that is used to set the presetter. Our newest Mazak, an FH8800 has a tool eye and is with'in .0005" of the presetter. As for the electronic gages, there ok, at least as good as touching off your part if not better. They work by completing an electric circuit which lites the light inside.

[psychomill]

We use several different tool presetters here. I like the ones from Parlec quite a bit....

The electronic ones are quite accurate and more importantly, repeatable.

As far as your second question though.... are you asking how they physically work? or how well do they work? I get the feeling you don't understand the principles of external tool presetters. Is that correct? If you do, then I misunderstood your question...

[is300driver]

thanks for the recomendations. I understand how they physically work, i was curiouse about their accuracy. Sorry, poor wording.

thanks, alex.

[dertsap]

personal preference -- dowel pin

[psychomill]

Alex (is300driver)...

External presetters are dead accurate depending on environment. But even in many shop floor settings, they still maintain an extreme amount of accuracy. Your machine probably moves more than the presetter. Internal presetters (machine mounted types) are a little more susceptible movement. But with a certain degree of care and awareness, they can be fairly accurate as well (as AJL stated in his post).

Other benefits to them as well,.... faster setups, better repeatability, less operator error, can be wired directly to machines (no more typing in or bad keystrokes at the control), tool inspection and verification (one of the ones I use has a "zoom" lens... powerful enough that you can see the fine detail of the tool grind marks..... and measure that!), simplify programming for odd ball form tools (use of theoretical intersects for example on tool length and/or diameter).... etc, etc,

[ctate2000]

Save the money and use a feeler gage. They are cheap and dropping it does no damage. You can set a tool just as close and spend the money you save on more cutting tools. I like paper also. It is cheap too. Most machines today allow one button saves so fat fingering is less likely. I have used one of those LED buttons and it worked great until we left it on top of the part. 3 inch face mill will really send one of those things flying. After that we had a $100 chunk and new dent in sheet metal. Feeler gage will fly too but only cost $20 for a dozen.

[Konrad]

This one I built and didn't cost me anything, good for .001"

http://i25.photobucket.com/albums/c9...p/IMG_6204.jpg

Konrad

[gibbsman]

Tool presetters are great, the ones that we have at my shop are old but utimately are accurate enough, depending on the operator, at least within .001". Once you start cutting chances are that offset changes are going to be required for accurate work no matter how good the presetter is.

[psychomill]

Konrad,.... we have a few of those too. Works well and "home built"....

I think if you're looking to make a decision about buying one, there are some things to consider. The second part of the original question was how well and accurate presetters work. I think thats been answered.

As to comments made by ctate2000, that works too if you "have the time" so to speak. Many places still use those methods and many of the smaller shops will balk at the price of new presetters. And the fancier they get, the higher the price. A few things to note though in my experience. I still come across operators who fat fingers numbers even with the "one touch" button. Some guys also just don't seem to ever get the right "feel" with feeler gages. Blends are all over the map for many and amount of time it takes to back up a little to "fine adjust" is pure waste of time.

I'm not a big advocate for those electronic/laser/digital table pre-setters but its a step in the right direction. But as Ctate mentioned, don't forget it... they really do fly. Although I do use the built-in ones (like Mazaks, Makinos, retrofitted Renishaw, etc) for tool break checks durring machine cycles.

As far as "save the money". In our case, they "save money". In shops that are "busier than hell" will save also. A couple advantages... you can set all your tools for the next job offline while the machine is running. This saves a bunch on set up time as well as the first part accuracy and run. On long running jobs or jobs with lots of tooling, you can set a tool offline while the other tools are running and not have to interrupt the job to set a new tool. This is even more common for cell centers. I set a new tool all the time while a part is running on our cell centers. You can also use the same tools for multiple jobs on the same machine. Since you're setting positive tool offsets, you don't have to reset a tool to one of the parts, or both parts or to a table gage .

But either way, both are effective. One better than the other depending upon situation and what your plans on are in the near future...

[kalmah]

For mesuring the tool length, I've a Laser Blum control. As I test tool of 0.06mm, it's impossible to touch the peak, else Laser BLum is the best solution, but if there is oil on the tool, the measured length is false (too big)

[psychomill]

I've used and plan on adding some more laser setters as well ( in the machine ). Being able to measure a .06mm tool is not bad at all.

but if there is oil on the tool, the measured length is false (too big)

Not sure on Blum, but the laser setters I've used measure the tool while its spinning. The idea is so that you won't have coolant, oil or chips on the tool that way. If you can't spind the tool while measuring, then just spin the tool in the air for a few seconds with the coolant shut off. Maybe even an air blast through the spindle to avoid breaking the tool. Then measure the tool.