Tools Getting Dropped!!!!!!

[Thom Davies]

Hey Hows it all going?

The Therm is having probs @ the mo doing tool changes. its firing the holder out and it keeps going though the tool grippers. Ive cleaned everything and have put in new tool grippers. any ideas????

Cheers

Thom Davies

[Mark Hesketh]

might seem simple, but I know I often overlook the simple things... have you checked your air pressure?

and just for clarification, you're saying that the holder is going THROUGH the tool grippers, as in going too far? In the past, I have had a problem with the holder not getting pushed far enough into the grippers, but never too far.

[Forrest Chapman]

Thom,

If you have a machine older than a few years then the grippers do not have a positive stop on them. This is a simple add on from Thermwood and cost less than 5$ each. They bolt on under the gripper and stop the tool from popping thru. At the same time I would change all the grippers and put new rubber bands on them as it doesn't cost much.

Forrest

[Jody Wilmes]

The rubber band thing works great. It keeps the tension you need if this is the problem. I assume your pick-up/drop-off depths are set correctly.

[Thom Davies]

Hey Guys

I checked the air pressure and the was @ 80 PSI like the book should it should be @. When i cleaned the tools and inside i did change the grippers too. Didnt make a lick of difference. still fired it out and it sounds like a shot gun!!! I had a guy come in 2day the said it could be the claws inside that grip the tool. Also When the cutters are NOT underload they tool change fine. Its when its underload and does a tool change thats the prob.


Cheers

Thom Davies.

[Rob Frenette]

Hey Thom

Do all your tools do this or just your outline cutter?
Our 3/8 outline cutter makes that popping noise when it gets hot but it has not gone through the gripper. I try to keep the holder and inside the spindle clean to minimize the heat build up. I also change the collet on a regular bases and that seems to help with heat buildup. Have you tried some fine scotch brite to clean inside the spindle?

[Doug Gilford]

Hi Thom

I sent you an email this morning but had not heard a reply.

The first thing that needs to be done is to identify the source of the problem. The mostly likely in order are:

a) the tapers not being released cleanly due to dirty tapers
b) the tool gripper fingers being worn out and tired
c) the tapers not being cleanly released due to a damaged retnetion knob or a sticky draw bar or similar
d) high air pressure (secondary effect only)
e) the pick up location having been changed (but the user never touched it, we know)

(for the sake of those on lookers in this forum or those having similar problems looking for an answer, Thom had previously advised me that the tapers were thoroughly cleaned, so although that is the first place to look, I won't go there right now.)

Firstly we all need to understand the way in which a tool is released. Firstly the tool is released by the draw bar being relieved, and an application of compressed air into the spindle. As soon as the taper is released, the compressed air ceases to flow. If the spindle is not immediately released, more and more air will be applied until it is released.

Thom, have you cleaned insie the taper of the spindle with Kerosine and light steel wool?

Have you inspected the retention knobs?

Is it just one tool and no others? (if yes to this one, it indicates that excessive heat is being generated by the tool during cutting. This needs to be rectified. Your spindle speeds might be too high and your feed speeds might be too low on this tool. Alternatively you may have set your \"Double Pass Size\" too big or the \"% Full Feed for Through Cuts\" too large, or the \"Last Line Feed Speed\" or the \"Min Feed Speed\" too slow. All of these conditions will result in increased heat of your outline tool. Increased heat means decreased tool life and would almost certainly induce the problems you are having.)

The next thing to check is the performance of the tool holders. As Forrest mentioned, and I can confirm your machine machine does not have positive stops on the tool holders.

The best way to determine the performance of the tool holders (grippers) is by manually ejecting and inserting each of the tapers. If the tapers tends to fall into the gripper and seems to easily fall through the gripper fingers, then one of three things is the problem (or part of the problem) Firstly, the grippers themselves are fatigued and worn out. These can be replaced ane are quite inexpensive.
Secondly, the rubber gripper bands are either non existent (in your case) or worn out. Either way these need to be replaced.
Lastly, as it is in your case, you do not have any positive stops under the grippers.

I recommend that you order replacement grippers, rubber tensioning bands and lastly positive stoppers.

Thom, in your case, I believe this to be only a part of the problem. The fact that you mentioned that it shot out like a gun indicates improper ejection of the taper.

This is likely to be caused by only three things:
a) dirty tapers or spindle internal
b) damaged retention knobs
c) excessive heat build up

refer to my notes above on how to fix this.

let me know how it goes

[Michael Kowalczyk]

Hey Thom,
Have you solved this yet? If not I had the same issue with a long running tool. I use a 1/2\" PCD all day long and sometimes for days. It gets hot even though I have a good chip load. If it is a type writer type ATC then you may need to adjust the air pressure. Tech support can walk you through it. If it is a bar on the back, I am not sure because I have just added two of them to my C42 twin table so I have not had any problems with the tools. But I asked Thermwood and several Tool holder manufacturers what the coating was on the new tool holders when you take them out of the plastic bag they are wrapped in. It is only the everyday common WD-40. Yes can you believe that it is not very complicated. All you have to do is wipe it down with a paper towel to coat it lightly. I use a scotch brite pad (fine) spray the top of the holder and just give it a twirl. They look like new and I don't get the marks on the taper that I used to. I have not had any sticking/popping issues since.

Hey Doug, You said clean the inside with Kerosene and steel wool. What happens if a piece of steel wool gets stuck inside? Also the steel wool will get rusty unless you use a new one every time. I like the Scotch brite pads because they are non metallic and easy to get up inside the spindle. What do you think?

One other thing you should check is your air supply. Is it clean and DRY. I added an additional pre-filter at the tank to help mine.

Oh Thom By the way my daughter had a wonderful time down in Auckland this summer, I mean your winter.

Hope this helps,

[Doug Gilford]

Michael,
Thank you for pulling me up on that one regarding the steel wool.

I should have added that if your use steel wool then you must absolutely ensure that:
a) you use a new piece every time
b) ensure that there are no trace remnants left in the psindle by carefully wiping it with a clean dry cloth after the steel wool

I did not mentioned this previously as I thought common sense might prevail but I know I should not have assumed that.

I probably also should have mentioned that I myself use scotch brite and WD40.

Michael
If you are still experiencing excessive heat build up you need to check all of the following as all of these things can and will effect heat build up. Of course the secondary effect if tool ejection difficulties:

- Integrity of the tool (Clean sharp, no resin build up)
- spindle speeds vs Feed speeds (Main chip load)
- type of cutter are you using (is it suitable for plunging)
- \"Maximum Feed Size\" Setting
- \"Last Line Feed Speed\" Setting
- \"Min Feed Speeds\" Setting
- \"Double Pass Size\" Setting
- \"% Full Feed for through cuts\" Setting
- Dust Extraction performace
- Part Spacing
- Overall length of tool cutting flute size
- Compression point in relation to board thickness (we get specially ground compression tools with a longer upshear portion for cutting MDF. This lifts the compression point of the dust and gives the dust extractor a better chance of extracting the material)
- Dia of tool compared to thickness of board

(Thats enough heat factors for now)

hope this helps

[Thom Davies]

hey Guys

Thanks heaps for all the help Doug and mike.

Its sat and ive spent the day cleaning the tool holders and checking the air pressure. I took the holders to our stainless top place and got them buffed up. they look better than they did when they were new!!! I cleaned inside the taper and me and peter ( My dad and owner of the company) Checked the air pressure and stuff. Ive run a sheet, and tool changed like new! ive also put in the new tool grippers. I'll have to wait to c how it handles run over monday if we gonna have any more probs. Which i'll put on here what the out come is.

Thanks again,

Cheers

Thom Davies

[Thom Davies]

Hey Hows it going?

Just to let u guys know that the therm is running sweet as now. Tool changing is back to normal now.

Thanks

Thom Davies

[Doug Gilford]

Excellent Thom

Great news

[Michael Kowalczyk]

Glad to hear it is working good. Keep those toolholders clean

[Thom Davies]

I might of spoken too soon!!!!

Im now getting the brown build up again.

I got pics 2 show u.

And one one of the pics you can c the little dents that are on the holder!

The thermwood pushed it though the holder again as well.

[Thom Davies]

heres another pic