Deflection in Outline Cutting-Looking for Input Please!

Discuss Thermwood 3-axis Machinery, Controller, and Software.

Moderators: Jason Susnjara, Larry Epplin, Clint Buechlein, Rich Kasten

JohnLashuay
Guru Member
Posts: 645
Joined: Mon, Nov 20 2006, 3:39PM
Company Name: Rylex Custom Cabinetry-Close
Country: UNITED STATES
Location: Pine Island, New York
Contact:

Deflection in Outline Cutting-Looking for Input Please!

Postby JohnLashuay » Tue, Sep 28 2010, 11:28AM

Hi All!

We are using a 3/8" Compression bit to outline cut plywoods and melamines. What we have found is that when it double passes the deflection tends to be greater therefore causing the need to hand route these pieces to clean them up. Our remedy for this is to "climb" cut jobs that have a lot of double pass parts. The problem is that the single pass parts tend to not be as cleanly cut (a little fuzzy).

What is the possibility of being able to add an option to "climb cut" double pass parts and keep single pass parts "conventionally cut?"

Any feedback would be appreciated!

-John
Rylex Custom Cabinetry & Closets
http://www.rylexonline.com
Thermwood CS 43

User avatar
Josh Rayburn
eCabinets Beta Tester
Posts: 1260
Joined: Wed, Jul 01 2009, 2:19PM
Company Name: Halls Edge Inc
Country: UNITED STATES
Location: Stamford, CT USA
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby Josh Rayburn » Tue, Sep 28 2010, 11:47AM

John,
The only other thing you can do is to max pen the tool at half the material thickness, this will cause significantly less deflection.
You probably don't want to slow the tool down, because that's just going to cook it.
The problem is that this would of course cause ALL parts to be "double passed" according to the max pen, regardless of the parts' sizes.
Probably not helpful, but if you need to isolate parts that are problematic, you could try that strategy.
jnr
Josh Rayburn
Hall's Edge, Inc.
CNC Machining Service


Dell Precision T3400
Win7 Professional 64 Bit/Core2Duo E8400 3ghz/4 GB Ram/NVIDIA Quadro FX570

JohnLashuay
Guru Member
Posts: 645
Joined: Mon, Nov 20 2006, 3:39PM
Company Name: Rylex Custom Cabinetry-Close
Country: UNITED STATES
Location: Pine Island, New York
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby JohnLashuay » Tue, Sep 28 2010, 2:11PM

Thanks Josh!
I'd rather not cut in only half way. I am concerned that it would not hold down well enough.

Do you do much cutting of small parts that need to be double passed? If so are you getting the these results?

-John
Rylex Custom Cabinetry & Closets
http://www.rylexonline.com
Thermwood CS 43

User avatar
Josh Rayburn
eCabinets Beta Tester
Posts: 1260
Joined: Wed, Jul 01 2009, 2:19PM
Company Name: Halls Edge Inc
Country: UNITED STATES
Location: Stamford, CT USA
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby Josh Rayburn » Tue, Sep 28 2010, 3:02PM

Hi John,
Yes, I've cut lots of everything big and small!
Hold down is always a concern on the real tiny stuff, but the double pass feature has worked very well. I have a 25hp vacuum pump and it does the job very well.
I generally cut MDF core materials in two passes in a climb direction no matter what to make up for the deflection, but on veneer core materials, which have to be cut conventional to avoid the fuzz, it can be noticeable.
What feed speeds are you running at and what is your vacuum size? Also what thickness are you leaving the skin for your double pass parts?
If you run the tools into the ground, you've probably noticed how essential it is to re-tool for VC materials as well....

Another note, the tabbing feature in CN could use a little work - but a little birdie told me that this might get some attention in the future, just don't know exactly when. I've cut lots of V-Carve stuff too - and the Vectric tabbing feature is AWESOME and works very well, so hopefully if it's anything like that, then that might be a more practical and faster-machining-time solution in the future.
jnr
Josh Rayburn
Hall's Edge, Inc.
CNC Machining Service


Dell Precision T3400
Win7 Professional 64 Bit/Core2Duo E8400 3ghz/4 GB Ram/NVIDIA Quadro FX570

JohnLashuay
Guru Member
Posts: 645
Joined: Mon, Nov 20 2006, 3:39PM
Company Name: Rylex Custom Cabinetry-Close
Country: UNITED STATES
Location: Pine Island, New York
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby JohnLashuay » Wed, Sep 29 2010, 9:24AM

Josh Rayburn wrote:What feed speeds are you running at and what is your vacuum size?

our speeds are down around 400-500 depending on the tool
our vacuum pump is 18hp

Josh Rayburn wrote:Also what thickness are you leaving the skin for your double pass parts?

we leave .020"

Josh Rayburn wrote:If you run the tools into the ground, you've probably noticed how essential it is to re-tool for VC materials as well....

We have been careful about this because we have seen additional deflection the more the tool dulls.

Josh Rayburn wrote:Another note, the tabbing feature in CN could use a little work - but a little birdie told me that this might get some attention in the future, just don't know exactly when. I've cut lots of V-Carve stuff too - and the Vectric tabbing feature is AWESOME and works very well, so hopefully if it's anything like that, then that might be a more practical and faster-machining-time solution in the future.
jnr

We haven't looked into this feature yet.

Do you cut much with melamine?

-John
Rylex Custom Cabinetry & Closets
http://www.rylexonline.com
Thermwood CS 43

User avatar
Josh Rayburn
eCabinets Beta Tester
Posts: 1260
Joined: Wed, Jul 01 2009, 2:19PM
Company Name: Halls Edge Inc
Country: UNITED STATES
Location: Stamford, CT USA
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby Josh Rayburn » Wed, Sep 29 2010, 9:27AM

Tons of melamine. Literally :)
The melamine holds down much better since it's got a clean face that the air does not suck through, as I'm sure you've noticed too.
It is tough when the part is so small that it doesn't cut the skin at all, it gets a little messy. But, I make parts for other shops, so they all have a tablesaw and they are happy to deal with the real small stuff - the saw is the right tool for those jobs anyway.
jnr
Josh Rayburn
Hall's Edge, Inc.
CNC Machining Service


Dell Precision T3400
Win7 Professional 64 Bit/Core2Duo E8400 3ghz/4 GB Ram/NVIDIA Quadro FX570

JohnLashuay
Guru Member
Posts: 645
Joined: Mon, Nov 20 2006, 3:39PM
Company Name: Rylex Custom Cabinetry-Close
Country: UNITED STATES
Location: Pine Island, New York
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby JohnLashuay » Wed, Sep 29 2010, 9:45AM

We cut a lot of drawer boxes and we need to double pass about 90% of the parts. Because we blind dado our drawers, the saw is no longer an option (big reason for getting the cnc).

This is the main reason for the question. In order get the best yield, we try to nest the drawer parts into a job. This is where it would be great to be able to have an option for climb cutting the double pass parts only and conventional cutting on the single pass parts.

Would this option be a benefit to you?

-John
Rylex Custom Cabinetry & Closets
http://www.rylexonline.com
Thermwood CS 43

User avatar
Josh Rayburn
eCabinets Beta Tester
Posts: 1260
Joined: Wed, Jul 01 2009, 2:19PM
Company Name: Halls Edge Inc
Country: UNITED STATES
Location: Stamford, CT USA
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby Josh Rayburn » Wed, Sep 29 2010, 10:12AM

John,
Yes, that would be beneficial.
I'd really love to see the first pass (climb or conventional) leaving a skin, but OFF THE LINE by a user defined distance. Then the final pass could graze the edges and go through all the way. This way it does not matter what direction or material we're cutting, we know the deflection is gone because we're only grazing .020 off the outline on the final pass, and we get the cut direction we want. I've used this for DXF parts successfully for a long time.

As far as the drawer box parts, I rarely have anything move around on typical size boxes, i.e. 4" drawers are about the smallest I have to deal with on a regular basis.
jnr
Josh Rayburn
Hall's Edge, Inc.
CNC Machining Service


Dell Precision T3400
Win7 Professional 64 Bit/Core2Duo E8400 3ghz/4 GB Ram/NVIDIA Quadro FX570

JohnLashuay
Guru Member
Posts: 645
Joined: Mon, Nov 20 2006, 3:39PM
Company Name: Rylex Custom Cabinetry-Close
Country: UNITED STATES
Location: Pine Island, New York
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby JohnLashuay » Wed, Sep 29 2010, 10:32AM

That sounds great! That would allow a very small load on the tool which should reduce the deflection, right?
-John
Rylex Custom Cabinetry & Closets
http://www.rylexonline.com
Thermwood CS 43

User avatar
Josh Rayburn
eCabinets Beta Tester
Posts: 1260
Joined: Wed, Jul 01 2009, 2:19PM
Company Name: Halls Edge Inc
Country: UNITED STATES
Location: Stamford, CT USA
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby Josh Rayburn » Wed, Sep 29 2010, 10:59AM

Exactly. That's the ticket to parts with square edges and clean cuts.
Solids are much different, you can't take that approach or you'll get stuff tearing out all over the place, but it works perfectly for sheet goods. I only cut solids from DXF - manually programmed anyway.
jnr
Josh Rayburn
Hall's Edge, Inc.
CNC Machining Service


Dell Precision T3400
Win7 Professional 64 Bit/Core2Duo E8400 3ghz/4 GB Ram/NVIDIA Quadro FX570

Gary Campbell
Guru Member
Posts: 256
Joined: Sat, Apr 04 2009, 6:27PM
Company Name: ShopBot Tools Inc
Country: UNITED STATES
Location: Durham NC

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby Gary Campbell » Wed, Sep 29 2010, 7:51PM

Hey guys...
This conversation is a surprise to me as a ShopBot user. I cut a good number of parts using the SB Link. Due to greatly reduced vacuum capabilities and much greater machine deflection, most ShopBotters need all the help we can get to keep parts from moving and the correct size.

In the link, which I assume is a subset of your CN software, we are able to select "run opposite direction" for our final (skin removal) outline pass. Most of us run climb for the first pass, (or passes depending on settings) and then do a conventional (no load) pass to remove the skin. This seems to be the best of both worlds for our cutting needs. Deflection on cutting passes is into the waste, and final conventional passes are at little or no lead for very accurate parts with great edge quality.

I do dadoed (and blind) solid wood drawer parts using this method, tho some porous species like Oak, require leaving the skin on to be removed with a lam trimmer.

I am sure there is a terminology gap between our respective user groups, so please pardon my question of the obvious. John,when you say double pass, are you referring to a pass to skin depth and then the skin removal pass, or 2 less than full depth passes? My usual cutting for 3/4 ply or melamine is climb @ 400 ipm to .035 skin and same speed conventional to remove skin. Thanks for your time and sorry to interupt.
Gary Campbell
ShopBot Tools Production Support

ShopBot (eCabinets) Link Training & Support

JohnLashuay
Guru Member
Posts: 645
Joined: Mon, Nov 20 2006, 3:39PM
Company Name: Rylex Custom Cabinetry-Close
Country: UNITED STATES
Location: Pine Island, New York
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby JohnLashuay » Thu, Sep 30 2010, 8:59AM

Hi Gary! No need for apologies...thank you for your input!
Gary Campbell wrote:In the link, which I assume is a subset of your CN software, we are able to select "run opposite direction" for our final (skin removal) outline pass. Most of us run climb for the first pass, (or passes depending on settings) and then do a conventional (no load) pass to remove the skin. This seems to be the best of both worlds for our cutting needs. Deflection on cutting passes is into the waste, and final conventional passes are at little or no lead for very accurate parts with great edge quality.

This sounds like what I am looking for.
Gary Campbell wrote:John,when you say double pass, are you referring to a pass to skin depth and then the skin removal pass, or 2 less than full depth passes?

Yes, a double pass goes to a set skin depth. For us it is .02"

Thanks again Gary!
-John
Rylex Custom Cabinetry & Closets
http://www.rylexonline.com
Thermwood CS 43

User avatar
Jeremy Schiffer
eCabinets Beta Tester
Posts: 944
Joined: Tue, May 10 2005, 9:36PM
Location: Carnesville, GA
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby Jeremy Schiffer » Thu, Sep 30 2010, 10:51PM

Definitely count my vote on this one. That lip on double-pass parts is annoying, and either of those solutions (user-configurable "oversize cut" on the first pass, or a climb on first pass and conventional on second pass) would be greatly appreciated! It's no fun having to go back after the CNC to clean up edges by hand!
http://www.corlanecabinetry.com

Intel Core i7-5820 3.3GHz, 16GB RAM, NVidia Quadro K2200 4GB, Windows 8.1 Pro 64 bit

Keith Neal
Junior Member
Posts: 49
Joined: Tue, Mar 03 2009, 9:30AM
Company Name: Wilbedone Inc.
Location: Cortland,NY(upstate)USA
Contact:

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby Keith Neal » Fri, Oct 01 2010, 5:34AM

Count my vote as well, we cut mostly solid surface on our machine, it's hard to get a tight seam on the smaller pieces when they are double passed, the same for our 3cm material which needs to be cut in multiple passes due to thickness and density(otherwise we'd have to use a new bit for every sheet)-Keith

Gary Campbell
Guru Member
Posts: 256
Joined: Sat, Apr 04 2009, 6:27PM
Company Name: ShopBot Tools Inc
Country: UNITED STATES
Location: Durham NC

Re: Deflection in Outline Cutting-Looking for Input Please!

Postby Gary Campbell » Fri, Oct 01 2010, 8:54PM

Guys...
The "run opposite direction" for skin removal pass is an awesome feature. I lobbied long and hard for that one. I just assumed that your "big iron" didnt need the feature. I hope the programmer crew wont be miffed I let the cat out of the bag. But I bet they have a couple extra checkboxes laying around in a desk drawer for you guys.

Currently we are hoping to get a selectable cut order to allow drilling and dado cuts before PE thru cuts. This will afford those of us with small vac pumps to cut all the depth critical geometry before thru cuts start reducing the hold down, especially on plywood. Doesnt seem to affect melamine as much due to it is a flatter product. On some parts that have more PE cuts than others the tenon thickness is all over the place.
Gary Campbell
ShopBot Tools Production Support

ShopBot (eCabinets) Link Training & Support


Return to “Thermwood 3-Axis Machinery”

Who is online

Users browsing this forum: No registered users and 5 guests