[speedofsound]

Some of you may have seen my post inquiring about an upcoming purchase. Well, a trip to see this machine was positive, and the deal is done and it arrived at our shop today.

I look forward to getting to know you guys/gals and learn more about this machine. It's a 1998 MB 18 with Centurion VI control.

Alan

[moldcore]

Congratulations! Looks like a nice machine. Sorry don't know much about that model but do have the Centurion 6 controller on a VM24. If there is any thing we can do to help let us know. We use Surfcam to program so we don't use the controller much other than to download programs. Can't tell, but is the monitor a CRT or a LCD screen?

The table on that machine looks very low to the ground in the picture. To me that looks like an uncomfortable position if you'd be using the machine for manual work also. I'm 6'2" so most things look too short. Even on our manual Bridgeports, we have risers so the table can be used at a higher position.
Good luck!

[speedofsound]

Hey, a reply! Thank you, I appreciate you taking the time.

I'm not as tall as you, but agree the table would be a little low for manual use. Fortunately, this won't often be the case.

My friend and I plan to use this machine for our small business. We're both trying to feel our way around the machine and the controller to get comfortable. We have a couple of years experience on a benchtop mill, but this is all new to us. Gonna take it slow and learn as much as we can. Hopefully our questions won't be a bother.

The monitor is an LCD.

One thing puzzling us is how to get a tool down to the table. Not sure how we'd cut a 1/4" part, for example. If the quill is fed down, the power draw bar does not function properly. With the quill all the way up, it's fine. It's likely we're missing something very simple. Any advice is appreciated.

Alan

[One of Many]

This must be an R8 spindle? The power drawbar is only engaged when the quill is all the way up. That is the way it is , so it is working as designed. You do not want the power drawbar engaged with the spindle on. Drop the quill to disengage it before starting the spindle.


In the main menu, you will see a HDW F-key. Within this mode you can lower the head with the selected Z-axis using the Handwheel. Each HDW detent distance step rate can be set with the feed rate knob. This helps to give rapid or fine feed control in setups and quick milling without actually programming.

The Jog screen has similar functions, but can be controlled by the desired distance for each key press using the number keys as pictured in the graphics jog screen. You can zero out each axis in these mode too. Using the DIST key for point to point with feedrate control allows power feed in all axis.

In a programmed mode. You do have a lot of Z travel, but this is associated with the tool length offset. If you request a move in Z but get an error knowing the cutter should reach and the Z looks to have room to travel, the tool length setting can prevent a move it views as out of limits. It may just be the wrong tool offset or it is too close to the soft limits. With this machine, I'd expect that more in a positive Z, but it is something to be aware of. More of a newb learning curve, but it catches me every now and then. All be that on a different model machine.

The Z-tool (in HDW or JOG modes) is best done with the handwheel for better control. You can get close, drop the cutter to the top of material with the quill, the press SET Z or Z-tool(can't recall what that was off hand) and follow the prompts for cutter number and diameter. Although cutter diameter could be left at .000 if your cam software offsets for you. Coversational programs will need the cutter diameter set. After Z-zero is set for tool 1, do not move the quill again. All remaining tools must be set with the HDW against a tool setter or paper shim on top of the material, or the same surface as tool 1. Successive tools are/should always set in relation to tool 1.

As a word of caution. Whenever possible, get in the habit of using the mill with the quill at least an inch down(maybe 2") and locked and no top quill stop set. If there is a crash in the Z direction, the quill will be pushed up without doing immediate damage and this may also give you a chance to pull the quill up in an emergency condition during X and Y moves.

You really should get the operators/programming manual for this machine. It has a lot more details to keep you from developing bad habits that could risk the health of the machine. If you do not already have them, Maintenance manuals and schematics are a wise investment too.

DC

[speedofsound]

DC, I can't thank you enough for your speedy and thorough reply. We will review your tips tomorrow at the shop.

It is an R8 taper, with a Tormach tooling system being used. With the quill up, the drawbar works just fine as you stated.

My partner was perplexed that the Z axis could not be lowered enough for the tool to reach the table with the quill being lowered. It seems to defeat the purpose of the drawbar. Spacing the part upwards to meet the tool would seemingly invite inaccuracy.

The machine did come with manuals for the mill and controller. I can snap a pic of them to show you which ones were included tomorrow.

Thanks for your willingness to help. If cnczone gives out custom titles, I'm up for "total noob" with a 2 day old (to me) machine! haha

[mikesos1]

Hey guys, I am Alan's friend and partner. Maybe I can help shed a little more light on our issue.

Thanks for the info DC, We do have all the manuals for the machine but they are not answering my questions.

It is a R8 taper with a Kurt power drawbar. I see what you are saying about the tool offsets but we haven't tried to acually run a program yet.

Here is the issue in my words. Using the jog mode I jog the Z axis all the way down to it's lower limit. With the quill all the way up so the drawbar can engage, the face of the spindle is still 5-6 inches from the table. My tool is only 2.5 inches long so it is still no where near able to cut a thin piece of materieal on the table. I can drive the quill down but then I have to move the quill back up to do a tool change, I will lose my tool offsets when moving the quill. What am I missing? We have been using a Mini Mill for the last 2 years but this machine is a whole different animal.

Also it is a bed mill, so it has 20 inches of Z travel, I just need to figure out the bottom 5. HaHa.

Thanks for the help,

Mike

[One of Many]

How about the noob twins for a Zone nickname? Nah, just giving you a hard time!:stickpoke

I am not sure what the lowest Z down should be. A test could be to jog to the top, set Z-tool 1 to 0.000 there, then jog to the bottom and check full travel is what you are getting(make sure tool 1 is displayed as the current tool). When you are down, what does the Z display say? If you have not set a Z tool offset, this may limit the Z, but in jog or HDW, I wouldn't think so. It should still go limit sw. to limit sw. full physical travel. If you cannot get the cutter down to your material, how are you setting your Z-tool? If you must lower the quill full stroke, you will lose a lot more rigidity. That does not sound right, but don't know for sure. That dimension, minimum nose to table could be in the spec's somewhere.

As to losing the Z tool offset, this is where a lower quill stop could be helpful, but not very accurate. One of those LCD quill DRO's helps to reset the quill back to a known location to return the Z offset. Using just a quill stop to return to the Z-tool location is not as trustworthy.

The bad part of those power drawbar setups is needing to return the quill to the top. I know other quick change tooling is expensive, but over a very short period of time they repay with a lot less hassles. Check out the EZ-Change R8 system that Royal offers through MSC. Snap in tool changes when Z retracts to your tool change position and no quill movement required. We love them, although they are not for heavy hogging! I still push them pretty hard with cutters below 3/4".

I give you a month or three and I'll bet you have the control...uuuhmmmm , under control! LOL!

DC

[speedofsound]

Glad you spotted this, Mike.

[One of Many]

Not a problem Mike,


I am not a pro at your particular control or that model machine. Most of the Centurion controls past 1990 are pretty close, but do have different features on some. There are other users here with far more direct experience.

Looking at the mill pic again, I do see the Z square ways stop above the top of the table and the lower edge of the Z zaddle stops about the same depth as the spindle nose. I don't know if there is some parallax error in that view, but it looks as though the spindle nose may not be capable of touching the table closer than 5" with the quill up.

The sufferage of large Z travel machines not designed to be used without some form of workholding less than 5" thick I guess.

DC

[moldcore]

I'm certain the machine is design to keep the quill off the table to minimize damage. Having 5" of clearance with the quill retracted makes sense. The 5" is made up with the quill travel. You probably don't want to machine directly on the table. Put a sub plate on the table or use a vise.

From what I recall from using a Kurt power draw bar on a manual Bridgeport, running the spindle with the quill all the way up was ok. The Kurt's socket only moved down to engaged the draw bar when you pushed the button and raised when released.

Getting a scale for the quill like this one should help with accuracy:
http://www1.mscdirect.com/CGI/NNSRIT...MT4NO=12382059

[One of Many]

We have several of the Kurt power drawbar on manual machines, but I never use them. It makes a lot more sense to have the drive unit come down to the draw bar when the quill is all the way up. The kurts have a can over them, so I have not really seen them in action.

I have seen that DRO for much cheaper than $253. I thought they were running $130-170. Have not looked lately though.

I would have expected the Z travel within an inch of table, but 5" sure does limit the cutting capacity for that size machine. Then again I am surprized it is R8 instead of a 30 taper.

DC

[speedofsound]

Thanks to some of your tips from last night, we spent the afternoon cutting parts. We did indeed need to drive the quill down to work on some 3/8" acrylic on a 3/4" MDF board. There was no negative affect whatsoever. Coming from a mini mill, we both watched in awe of the speed and power.

Here's a couple shots of a test part, using our company logo as a "first part" out of the mill. We did a little 3D milling after that, and it was a big success.

No doubt we'll need your help again (soon!), so I sincerely appreciate the time you guys took to lend a hand.

Alan

[One of Many]

Nicely done! What core business, relative to speed of sound do you offer?

The first part I did on my EZ-trak was my Wifes name in aluminum........just to show what its capability was without a lot of technical terms. I guess that worked, since she is letting me bring home a 1999 Milltronics VK3. That was supposed to happen in October, now delayed until January. It is paid for, but its replacement has not come in yet.

Cutting plastic won't become as much of an issue with the quill lowered. Heavy cuts in aluminum and steel can. Between chatter and deflection, it will become more evident as you push the machine harder. Just as with the mini-mill, you will learn to live within the new found limtations, but this is on a grander scale.

Congrat's to you both for getting this far in a short amount of time. Upward and onward!

DC

[speedofsound]

It's easier to explain our core business if I just point you to our website: www.speedofsoundllc.com

The CNC operation for our gauge holder product is a 3D relief which allows our injection molded "bullet" to recess into the pillar cover. To present, we've farmed this work out, with its fair share of frustrations. This new mill brings with it a freedom from dependence on others for such a critical step in our mfg. process.

Beyond the gauge pillars, we've developed several other interior components which we'll make short production runs on. Here's a nitrous oxide control panel for the 2005-present Ford Mustang (cut on our Taig):



Rigidity certainly wasn't an issue with the acrylic. It was hard not to laugh as we watched the mill power through the piece, taking cuts that would likely destroy our Taig mill. LOL

6061 will likely be the toughest material this mill will see. Mike and I will just need to determine what a "heavy" cut actually is with this machine. Couldn't take more than a few thousandths at a time with alum. on the mini mill. This nitrous bottle bracket is representative of what we'll be cutting (this part was farmed out, cut on a Milltronics RH20):



Your comment about living within the box is dead on. We're happy to have moved into a big one! 12 x 6 x 6 (barely) was getting old...

Onward and upward is right, but we're going to keep the steps (literal and figurative) small for a while.

Alan

[mikesos1]

Thanks Again for the help guys, it's nice to have a resource like this around, what did we do before the internet? HaHa.

I found one of those Quill DRO units on Ebay for 70 bucks, so I got that. That should allow me to accuratly position the quill down where I need it to cut, then raise it back to do a tool change, right? That way I could do tool changes in the middle of a program without losing the tool offsets?

Also is there a good resource that you know of explaing tool and work offsets that might be easier to understand than the Centurion manual. I haven't quite got my mind around this concept yet. I get it at a basic level but not sure how to translate that to programming and running the machine.

Thanks again, you guys rule! :cheers:

Mike

[One of Many]

I found one of those Quill DRO units on Ebay for 70 bucks, so I got that. That should allow me to accuratly position the quill down where I need it to cut, then raise it back to do a tool change, right? That way I could do tool changes in the middle of a program without losing the tool offsets?Mike

I have seen a few on Ebay, but do not know the quality. Mitutoyo's are decent quality and mount easy. So, if you found one of those at $70 you did good.

The reader head is coupled to the quill via the quill lug ring that moves with the quill on the quill stop assy. For the sake of repeatability, the coupling method needs to have little or no dead zone(free play with no motion).

A weak mount can also contribute a dead zone if flex is a result of too much drag on the reader head slide or change in direction spring. You can check its repeatability against an indicator. +/- .001 would be a minimum to shoot for after each tool change. Provided the power draw bar has a consistant pull.

Once your quill is locked, Z-tool is set, then reset Zero button on the quill DRO. You can set the quill stop for production benefits to return to the stop check the DRO until you return to the 0.0000 position. It is convenient to compensate for slight Z depth adjustments on the fly too.

DC