[Vern Smith]

I have the Haas GT-10 chucker lathe that is designed to make small parts. I make a lot of parts that certainly qualify and the lathe does a nice job making them. My problem is finding the parts after I’ve run through a 36” bar of ½” 6061. A common example was yesterdays exercise. A top hat shaped part .215 long with an OD of .4 at one end stepping down to .165 at the other and a .110 hole drilled through it. The little tightly wound spring that the cut off OP generated comes off bigger than the part itself.

So --- I need suggestions on somehow separating the parts from the rest and keeping them in one location. I made a basket that fits under the spindle but fewer than 20% ended up in it. Most of them dropped to the ledge under the turret nicely comingled with the swarf.

I have dreamed up various devices that would work much like my Royal cutoff/bar puller, coming into the side of the part while it is still barely hanging onto the protruding bar stock and breaking it off but the next problem is getting it off the “part grabber” for a better term and depositing it into some type of container.

I was hoping some of you may have had similar problems and have come up with the silver bullet without getting a patent of it.

Vern

[MILLMARK]

NO SILVER BULLET, BUT SLOWING THE SPINDLE DOWN JUST BEFORE THE PART BREAKS OFF WILL USUALLY LET THE PART FALL STRAIGHT DOWN, SO MORE WILL END UP IN YOUR BUCKET.

[BobWarfield]

Watching this video gave me the crazy idea that a ShopVac would be ideal as a small parts catcher:

http://www.youtube.com/user/TsugamiS...11/HRZoJVncwBk

Cheers,

BW

[Vern Smith]

Thanks for the suggestions. My problem with slowing the spindle down is my CAM software will not do it. Next time I'll just have to take the time to figure out how to hand code it.

The vacuum set up is intriguing. I have the M relays open to do it and a friend who has already figured out how to make it all work so I could incorporate the snap off tool with turning on a shop vac with the G code. If I ever get it accomplished I'll post a video

Vern

[Geof]

You can easily enter a spindle speed command. Step through the parting sequence in Single Block and look at the code; you will see something like this:

M03 S2000 (or something like that)
(there may be an approach move just clear of the part)
G00 X0.5 Z-0.215 (move to part-off position)
G01 X0. F0.003 (part down to X zero)
(retract moves)

What you want is:

M03 S2000 (or something like that)
(there may be an approach move just clear of the part)
G00 X0.5 Z-0.215 (move to part-off position)
G01 X0.1 F0.003 (part almost to the drilled hole)
M03 S500 (slow the spindle)
{Optional M code to turn on shop vac}
G01 X0. F0.003 (part down to X zero)
(retract moves)

Have your shop vac pick up tube just beside the parting tool. Actually you will need a stub of tube fixed adjacent to the parting tool and this comes into alignment with the tube running to the vac that is mounted on the cross slide out of the way of other tools.

[Vern Smith]

With all this imaginative help I guess I'll have to build the vacuum system and do the G code implant Video to follow, I hope.

Vern

[Mr.Xtreme]

Vern,

I cut very small parts and pins 2mm in dia, and .09 in length on an sl-10 all the time.
Also lose very few. The coolant is also culprit which is blasting your parts away from the catcher.
Here are some things we do.........

Measure the nib that is left on part and know the dia it separated from the stock material.
For example if the nib dia is .02 dia then program the cut-off X dia to roughly .050, then program a M9, then program another X move to complete the cut-off. Some other things you might need to do if they still kick away is adjust and lower the spindle speed and sometimes the feedrate right before seperation. Also you might put a dwell in for 1 sec to allow the cutting pressure to reduce just before it separates. With a little tweaking all the small items will make the catcher.
Another thing is we very rarely use constant surface speed for cut off.
We use a fixed spindle speed.
You can also find a catch bin to use with small holes in bottom or sides.
Actually I use a plastic square spaghetti strainer and if items are smaller then holes in that we line interior with a rag or cloth. When all is finished we dump it on a work bench on towels and get the tweasers out. Also we shim and raise the catcher up at times so its not too far below spindle.
Also to sample the parts during running so you can measure because machine sizes change and need adjustment while machine is running we slip either a strainer with a handle or hold a plastic can right under the part and let it fall into it. If you need time to get the can ready to catch the part after the water shuts off just hit feed hold for a sec till you position the can and then resume. With some tweaking and practice you will hit the goal 99% of the time.

Hopes this helps you.

Paul

[Vern Smith]

I appreciate all the suggestions as well as some help that came by phone from a lurking friend. Below is my first quick and dirty solution. It caught 24 out of 26 pieces and that's very acceptable considering the serious lack of effort or fore thought that went into it. Most of the parts went into the bucket after bouncing off the sheet metal semi funnel, for lack of a better term.

The major draw back to this system is it also captures about 25% of the swarf as well. I really thought it would catch more swarf than that but it looks like the high pressure coolant blows most of the swarf well away from the bucket. As you can see, the GT-10 does not come with a parts catcher. I'm sure one could be made but I think the vacuum system previously discussed would be simpler to make and probably just as effective.

I used Geof's G code magic to slow the spindle and turned the coolant off as previously suggested as well. It always gripes me when someone posts a request for suggestions for a specific problem on these forums and never replies with their results. If everyone did that those of you that take the time to help might not bother.

Vern

[HelicopterJohn]

Hi Vern,

You are so right about the help Geof, Paul, Bob, MILLMARK and others here on the forum provide. They are surely a life saver for guys like me.

Maybe you could contact cement a piece of thin sheet rubber to the face of your bouncing board or change the shape slightly. Might change the bounce path and get to that 100% efficencey rating.

Just another one of my thoughts that probably won't work.

Glad to hear your success story. Thanks for sharing the photo.

John AKA The Lurker

[Geof]

....It always gripes me when someone posts a request for suggestions for a specific problem on these forums and never replies with their results. If everyone did that those of you that take the time to help might not bother.

Vern

Yes it is a bit annoying when there is no feedback, but I blaim the parents for not teaching their children the oldfashioned thing about writing thankyou letters for gifts.

Re "G-code magic". Arthur C. Clark the writer is attributed with the comment: "any sufficiently advanced technology to the un-initiated is indistinguishable from magic". I think he is correct.

[Vern Smith]

Yes, Arthur was one of my favorites, if I remember correctly Childhood's End was very enjoyable, but of course I was young and uninitiated then.

Helicopter John, now you are trying to make things expensive, I already have over $10.00 invested in the project.

Vern

[roundman]

We have a SL10 and I have had similar problems. What I did was to extend the parts catcher ramp with Brass shim and clamp it to my existing ramp. Also if I can I will use as small a part off blade as possible width wise. Plus I adjust the feed and speed to prevent flipping of the part god knows where with too much force. Even then from time to time I will put in a M00 after the partoff and this will keep the ramp extended up because sometimes the part does not have enough momentum to roll down the part catcher ramp and so I just take the part or push it into the part holding box. I only only do this because it takes a lot of time to fish out parts when they drop down in to the machine basin. I have also laid down a apron or something and spread it out so I can see the part when it drops on this. It can lead to coolant draining slower if I do not allow a gap towards the back. (away from the spindle)

[roundman]

To all of you guys I want to say thankyou. The help here and the information makes me enjoy this trade more. Geoff is right appreciation and feedback is a wonderful thing and as far as I am concerned I am deeply grateful to you fellows.

[Ydna]

In the past I've made a few different tool attachments that were meant to break a part off once the parting operation was finished (I'd leave a small stalk to retain the workpiece). The break-off tool would move in, cup the part, and make a +X move to snap it off. Then once the break-off tool gets filled up with a few parts, the operator would need to empty it. (usually around 6 pieces depending on the size of them)

That only works with certain items depending on how they're shaped. The other thing I like to do with short parts that involve a boring bar operation is to let the boring bar itself break the parts away. You perform the parting operation then have the boring bar slip inside the part and peck away until the part is released (works best with through-hole workpieces). The part then falls onto the bar and provides a good spot to remove it. Just have to be careful not to scratch anything when pulling it off.

If you were running a dual-turret lathe, you can get really creative....but that's probably not the case here.

[APP]

I have used a piece of coathanger that I bolted to whatever available fastener was in the area of the part off tool, bent it just right so it caught the part in the id as it separated. If I got the bend just right, as the turret changed position it would drop the part exactly where I wanted.

[double a-ron]

Mr.Xtreme, your idea worked perfect for me. I did exactly what you said and I got 20 out of 20 .75" long parts made from .3125" hex stock to make it to the parts catcher bin of my TL-15. Thanks, now I'm going to have GibbsCam edit my post with that part off mod written into it.

[Mr.Xtreme]

Double A Ron

Cool, Glad it worked for you.

[roundman]

I reread all the posts and now I am thinking of adding a spegetti strainer to my stuff. I had these teflon parts .163 +.002 - .000 od and .075 long + - .005 long with id of .048 + .003 -.000 .... Well I ended up turning off the coolant on the partoff (.042 wide thinbit) process and holding a piece of scotchbrite and that captured it. I have to find a better way. Plus too there was a slight burr of + .005 on the overall length even after cutting the tube type burr off the end with an exacto knife. I would still have to rub the part on 320 white sandpaper to get the oal to about .077. I guess I could have lessened the oal .003 or so and the check would have been in tolerance with the slight lip left. I did notice that when the coolant is on it is like a rapid for that virgin teflon and it would just wash it away to parts unknown. This is on the SL10. Once again thanks Geoff (I hear ya on the thankyous) for the tips on the speeds and the G04 pause I will try lessening the speed to 500 or so at the exact partoff point.

[03clipse]

we have a little mini lathe. we made some parts onetime around .100 od with
.062 thru hole. had same problem of losing parts. we just used a straightend paper clip fixed to the cutoff tool post. move the cutoff in just right and it stuck the paperclip in the part and wala small part catcher

[Vern Smith]

I'm still trying to improve on the poor man's part accumulator. I took a significant step up the investment ladder with some 1/16 soft aluminum and a piece of .018 brass sheet with .025 holes on .04 centers. The plastic waste basket with the "pet" rated screen bottom worked but did not fit the trough real well and was hard to keep in place. The biggest problem however was the weave in the screen which allowed the ends of the swarf to embed themselves in the screen. After a few runs the screen would be coated with swarf that was very difficult to remove. It also made getting all the parts out harder and was tough on the fingers.

The fine hole brass sheet lets the coolant out but does not catch the ends of the swarf, much easier to unload and clean. I've been thinking about keeping the parts separated from the swarf and think the easy answer may be something to cover the parts bucket during everything but Geof's slow gentle final cut off operation. If the cover had a slight angle and one of the coolant nozzles was plumbed to wash it toward the back of the trough it might work pretty well. Any ideas on how to fabricate it? The previously discussed M code would be the way to trigger it and maybe air could be used to power it rather then some complicated electrical system that would probably electrocute me.

Vern