twd thickness change

[chunkstyle]

Just ordered my Link today and I have to contemplate the router bits I need to order in.

One thing that occurs to me is that, now that I am responsible for cutting my cab parts out instead of subbing it out to a Thermwood shop, is that I have to contend with the material thickness variations and tooling.

I've always used an average material thickness for my sheet stock library when creating my cabinets. I'm drawing with .469" and .72" with the ply and .76" with the white melamine as this has usually put us close on the Thermwood. Often, however, we get a batch of sheet stock that is different enuff to require a material thickness change at the TWD file generation.

Since the dadoe thickness is an percentage (I still don't know why it is and not a direct value) I realize that I'm also going to get tooling errors if I change my thickness value to anything that's under the original material that the files were created with.

Since I have to get some cutters ordered I'm looking at solutions to this problem. I'm thinking that I'll need to get a bit that will be slightly smaller that the designed mortise width and have that in the tool library as well?

Another possibility would be to create a % value of, say, 60% of material thickness as a hedge against going under your tooling diameter. This seems less efficient, tool path wise, but more than if you had a tooling error to deal with?

Just wondering how others are dealing with the thickness change as it effects their tooling. Going thru the tool catalgues and considering what to plan on getting.


Thanks,
Tim

[ken_rychlik]

Do you have an auto tool change machine?

If not you will want to plan on the least number of tool changes possible.

When you have a stack of plywood to cut and have to change bits several times per sheet it gets old quick.

You have already dealt with material thickness issues and it's best to wait to make the final twd until after you have your material at hand.

Kenneth

[chunkstyle]

Thanks Kenneth,

I've always used materials that were "close" to actual real world averages when drawing and then changed the material thickness after the sheet stock was delivered and checked. Problem that has occurred in the past was when your running into a tooling error that puts your mortises width below the tooling that was available at the machine (Thermwood shop's machine, that is).

I don't have an ATC and can appreciate the need to be conservative with the tool changes.

It just occurred to me that if I am running .5" material and am cutting with a .25" bit I may run into a problem with the tenon thickness percentage making my mortises les than .25" wide after a material thickness change at the TWD.

The outsource Thermwood shop relied on a smaller diameter bit in the machine for this type of issue (after learning the hard way). I was wondering if that is what Link users do as well?
I have some book shelf's that I'm designing right now for the eventual arrival of the link. They're getting .5" material for backs blind dadoed into the sides. Top's, sides and decks are .75" material. Shelves are getting 5mm shelf pin holes (still have a big sack of em to use up).

Since I have no experience with how the link addresses manual tool changes, I thought I'd ask about this issue as it's been a problem in the past and would like to deal with it while I'm drawing the cabinets up. If there is a tool in my tool files that is, say, 5mm does the link know to ask for the 5mm bit (not a drill bit but a regular bit) instead of the .25" bit for mortising?

Thanks again, I appreciate the input.
Tim

[Gary Campbell]

Tim...
You need to make one selection and then base the other on it. In other words, select either your dado width/depth and then get a bit to do it or select a bit and set dado parameters around the bit. The second is the preferred method for most users that dont have an ATC machine.

I will give examples for 3/8 MC bit, which is my bit of chioce for single bit cutting. 3/8 bits cut faster than 1/4 and MUCH faster than 5mm.

Set your parameters for blind dados so that the width is not less than the bit diameter (usually around 55-60%). Your depth cannot be less than the bit diameter. Full dados work best when material thickness is 110 to 180% of bit diameter. This gives some "move over" room for bit cooling and keeps within the stepover range that works well.

Remember that dados are cut as rectangles, which are way faster than pocketed areas.

Take care to enter a material thickness that is accurate AND taken from the interior of the sheet. (usually after a test cut for speeds, feeds and dado tolerances). This will give you the best fitting parts. Remember that when you change MTL thickness, dados are moved to match mtl thickness

[ken_rychlik]

Try to find some damaged sheet goods from your supplier to practice on after you get the link. You will need it.

Any bit will work to destroy junky plywood. :D

You can mike your bits before you run them, or mike your dado's after you cut a few and know what will work.

Mainly just trial and errrrooorrr.

[chunkstyle]

Thanks Gary & Kenneth,

I'll keep your advice in mind. Real good idea about the Junk sheets Kenneth.

I'll hunker down with the link manual and try and get a handle on how it's going to behave, in theory at least.

Much appreciated,
Tim

[Gary Campbell]

Tim...
Try using a 3/8 bit, 55% for the blind dados on the 3/4 mtl and use a full dado for the 1/2" back. Depths are 3/8 on the blind dado and use 1/4 for the back.

put in those settings and see how it looks

[ken_rychlik]

Gary, I need to try running the 3/8 some instead of the 1/4 inch, but I remember having issues getting two cabinet bases to nest side by side.

It would only nest 2 on a full sheet.

Are you using 49x97 material with the 3/8 bit?

Kenneth

[Gary Campbell]

Kenneth...
No, 48x96. Maybe the real question is... what is the depth of my bases?
Answer... less than yours so that the 3/8 bit works.

Real answer is we dont do kitchens, so the "standard" depth does not apply to our work. In any event, I dont need 2 bases to nest together on the same sheet like I used to think I did when I used a saw. The software will utilize the material in the best manner.

[nat_wheatley]

Kenneth,

I just tried, and was able to nest 2 - 24" wide pieces across a 49" sheet, using a 3/8" bit. For a while the software wasn't doing this, when it should have been able to. May be a fix in there. Might be worth giving it another shot.

Nat