problem solution

Michael Yeargain · Post by **Michael Yeargain** » Sun, Jun 25 2006, 7:34AM

Hey Jason and staff,

I had the pleasant opportunity to speak with Don Jones during his visit to our shop, concerning the acquisition of a router. At some point during the conversation I had this fabulous epiphany.

My thought was the use of a \"sensor\" to prohibit the tool from penetrating the aluminum bed on the machine. Don Jones made the comment that there is a automatic tool depth sensor built into the Thermwood already. So my suggestion is use this same automatic tool depth sensor technology to stop the bit before it plunges into the aluminum bed of the router. Thus regardless of the accidental miscalibrations of the tooling this will save potentially thousands of dollars in damages to the machines.

The use of a \"capacitance sensor\" may be more efficient in this application for the reason of the variations in the density and moisture content of the material. however the details will need to be worked out through trial and error and of course you gurus of all gurus.

Post by **Jason Susnjara** » Mon, Jun 26 2006, 2:04PM

Hi Michael,

I will have to ask our engineering dept. about this.

thanks,

Post by **Jason Susnjara** » Wed, Jul 05 2006, 10:01AM

Hi Michael,

The programmers are planning work for a max depth per tool to provide this type of functionality.

thanks,

Forrest Chapman · Post by **Forrest Chapman** » Wed, Jul 05 2006, 11:49AM

Jason,

I always understood the head has a Z stop that doesn't allow it to plunge below the tool collet. At least thats were it seemed to stop the few times I crashed it. I didn't think it ever hit the hard stop at the bottom of the screw.

I have mentioned this before about an onboard code that won't allow the tip of the tool to go x amount below the spoilboard. It will have to allow some of coarse because some guys don't use wasteboards. This seems like a more simple solution.

Forrest

Post by **Jason Susnjara** » Wed, Jul 05 2006, 12:38PM

Hi Forrest,

I believe the collet will extend below the table on the machine. The reason it stopped short of it is probably because of the sensor each axis has a load limit and that limit was met before the collet hit the table. If the collet does hit the table, it should stop right away becasue of that load limit. I think that the msu can be changed so that the collet doesn't extend past the table but you would need to speak to tech services about that.

Bill Rutherford · Post by **Bill Rutherford** » Wed, Jul 05 2006, 2:22PM

Jason,
Regarding the max depth per tool you spoke about. If this would rely on the daylight value of the tool then it would only be partially effective. The type of solution Michael suggested would be a bit more thorough; if harder to implement with noise issues and such. I would love to see something to stop the bit from plunging in to the table regardless of the the daylight value. The few \"crashes\" we have had have been the result of the wrong tool being loaded (and thus the wrong daylight value) I know ultimately it falls to the operator to know his tools, but if the machine could be made \"idiot\" proof it would be nice.

Michael Yeargain · Post by **Michael Yeargain** » Wed, Jul 05 2006, 5:35PM

Exactly,

this would nearly prevent an accidental plung even if the wrong bit is in the spindle. I do think it will be a little tricky, however the money savings out of down time (bondo for those who know what i mean).

It has happened before that the machine for some reason pick up the wrong bit or operator error installs the wrong bit during a changeover. And what a disaster that would cause.

I personally don't have a router YET but I am working on it.

You guy keep this going it is an invaluable solution.

Bill Rutherford · Post by **Bill Rutherford** » Thu, Jul 06 2006, 5:42AM

Michael,
As I posted above it would be a nice feature, but I am not sure it should be at the top of the list. I have been running Thermwood routers for three years (two different machines at two different companies) and have yet to run a bit into the table. We have broken one or two bits as we went into the spoil board but never actually hit the table. That said it would be nice to know that we could not actually hit the table.

Forrest Chapman · Post by **Forrest Chapman** » Thu, Jul 06 2006, 8:12AM

Bill,

Murphy's law, (your an accident waiting to happen). Sooner or later everyone is going to crash. I haven't heard of any other machine companies who have a function like this. I have never crashed because of the tool always because of code or the operator putting the wrong Zshift in the old flycut program.

With the old flycut program we had from thermwood the M61L8 code was M61L18 which didn't work. So one day my operator is doing a flycut useing the 2\" not the 5\" and he plows at 1000ipm into this steel popup pin. It made a very unpleasant sound. So we had some nylon pins machined and now if they don't go down it won't kill the bit or anything else for that matter.

I still think the the best way to prevent a major crash is useing the daylight value of each bit as a maximum plunge + a little. This will not stop some very long bits that haven't been tool lenght but most bits are placed about the same lenght out of the head and usually the larger bits are more closely watched.

Forrest

Bill Rutherford · Post by **Bill Rutherford** » Thu, Jul 06 2006, 10:58AM

Forrest,
As for an accident waiting to happen, don't I know it. I thought long and hard before putting in writting that we had never hit the bed

Don't want to anger the router gods!!

As for hitting a steel pop up pin, I can do you one better. My operator forgot to take the fly cutting tool out before machining regular parts. A long story short, it turns out fly cutting tools don't work too well for cutting dados. I have a fly cutter that is bent into almost an \"L\" as the proof. Thankfully he hit the e-stop as soon as it happened, I am not sure if the machine would have shut down due to limits and a heavy tool like that, out of balance would not have taken very long to have a major impact on spindle life!!! After that we took the fly cutter tool and painted all the non contact points of the tool and the holder with red spray paint to help draw attention. We also mounted the holder for the fly cutter right to the cabinet, near the screen to try and avoid it ever happening again.

As for the orignal suggestion to prevent the tool from cutting into the bed, if it was EASY to implement it would be a nice touch, but I certainly would not consider it a priority.

Post by **Jason Susnjara** » Thu, Jul 06 2006, 11:53AM

Hi Guys,

The programmers are planning work for a max depth per tool so that it would be hard to crash tool into the table.

Forrest Chapman · Post by **Forrest Chapman** » Thu, Jul 06 2006, 12:14PM

Hey Jason,

That sounds great.

Bill, I've got another happened on more than one occasion thing. We use a 5\" flycutter now and this tool cannot fit in the typewriter changer and when we had the 4 tool holder bars on the end of the table the offset for side entry was not sufficiant to clear the tool. So we slammed the tool down and broke the plastic holder and bent the metal bar down. Had to heat and bend that bar back on more than one occasion. Hasn't happened in a while (knock on wood).

I still think catching the table on fire is one of the better stories.

Forrest

Post by **Jason Susnjara** » Thu, Jul 06 2006, 12:16PM

Hi Forrest,

Just a little FYI. You should not be using a 5\" diameter cutter bit on the machine unless you lower the RPMs. We use and sell a insert flycutter that is 2\" in diameter. This will fit into the typewriter tool changer.

Forrest Chapman · Post by **Forrest Chapman** » Thu, Jul 06 2006, 3:55PM

Jason,

Are you sure 24,000 rpm is to high?

Just kidding, were running it at 9000rpm which is what the panel processing company we bought it from told us to run it. It runs fairly quiet and does a good job.

I did buy another 2\" flycut after mangling the first and use it to flat plane large lumber.

Forrest

Post by **Jason Susnjara** » Thu, Jul 06 2006, 3:57PM

Forrest,

Cool, I just wanted to make sure.