CNC

You are not logged in. [ Login ] Why log in
(NOTE: Login is not required to post)

Time Per 3/4 ply sheet on CNC

9/23/16       
Mike M. Member

We’re running a Biesse Skill with two Busch MM 1322 AV vac pumps and generating our nests with CV. I have True-Shape-Nesting and pack my parts fairly tightly. We make booth seating for restaurants so the parts are smaller than a typical cabinet job, with that, I feel like I have to keep the feed rate lower to keep the parts from flying off the table (we still generally chew up 2 parts per 10 nests. We do use an onion skin but trim that on a final pass for the smaller parts. Our go-to bit for cutting most of our ¾ panels is the Onsrud 60-173MW which is a ½” two-flute spiral compression with about 1/8” up-shear. We run the bit @ 410 IPM and 10,000 RMP. It usually takes about 13 minutes to cut one nest and we obviously would like to cut that down.
My question to all you folks is; what tool are you using to cut ¾ ply, and what is your speed and feed? Any thoughts on how I can improve my time?

I've attached a typical nest diagram for your review.

Thank you.


View higher quality, full size image (636 X 356)

9/23/16       #2: Time Per 3/4 ply sheet on CNC ...
Dropout Member

Is edge finish important?

Is cutting time? Would be be willing to add 5 minutes if you didn't lose any parts?

Could you tab them and clean up the tabs offline?

9/23/16       #3: Time Per 3/4 ply sheet on CNC ...
Mike M. Member

In this case, edge finish is not important. I want to be able to speed things up with as few broken parts as possible.

As far as Tabs, I haven't had a great deal of luck with them in CV, I thought it was yet another broken feature so I left it be.

9/23/16       #4: Time Per 3/4 ply sheet on CNC ...
Dropout Member

I wouldn't try this without tabbing. 0.750 long, 01875 thick.

I would use a 3/8 slow helix down shear or compression roughing bit. 1/2 is too big.

I'm also starting to experiment with plastic pin nails to hold plywood down.

I do a lot of this at 600 plus IPM.

9/23/16       #5: Time Per 3/4 ply sheet on CNC ...
Mike M. Member

Okay, good information, thanks. Can you post your tooling #? I'll give tabs another try as well.

9/23/16       #6: Time Per 3/4 ply sheet on CNC ...
Dropout Member

Onsrud 60-038 or similar.

Could try a 037 too for better chip evacuation.

9/23/16       #7: Time Per 3/4 ply sheet on CNC ...
Mike M. Member

It's nice to have a solid direction to go in, thanks for your help.

9/23/16       #8: Time Per 3/4 ply sheet on CNC ...
Mark

When cutting diewall parts, which are not too dissimilar from what you are describing I onion skin at 720 with a Vortex 3130XP, which has about 1/2 inch of up shear, mostly for chip evacuation and edge quality. I have plenty of vacuum, but no amount of vacuum is going to get 100 percent of veneer core plywood parts cut without screwing a few of them to the table.
I don't know if you can do it in CV, but in AlphaCam I can pretty quickly adjust the starting and stopping points of each perimeter path then order the tool paths to leave the largest part cut last. This way each part in a nest is still attached to the main body of until the cut is just about complete. If there are no large parts or if I need to end with a smaller one I place a couple of 5mm holes in the last part or two in a nest to be cut and screw them down to the spoil board. If a part is very small it gets a screw in it as well.
If you do a ton of this stuff Thermwood has a machine with a hold down roller for just this kind of thing.


View higher quality, full size image (1136 X 861)

9/23/16       #9: Time Per 3/4 ply sheet on CNC ...
B.H. Davis Member

I would go to a downcut spiral or compression bit. You will have less upward pull on the small parts at the sacrifice of a shorter bit life though.

Would it be possible to program this so only the smaller parts get onion skinned? That would speed things up a bit......as long as the larger parts are big enough to stay in place on their own.

BH Davis

9/23/16       #10: Time Per 3/4 ply sheet on CNC ...
Leland Thomasset  Member

Website: http://www.cnc-cabinetparts.com

I would use a Vortex Ex series 3/8" 25% less force on the part to move it plus more material to machine. I run plywood at 18k rpm 700ipm and down at 350 down.

9/24/16       #11: Time Per 3/4 ply sheet on CNC ...
cabinetmaker

I got so sick of losing parts or banana parts for the speed we are running I started to run return onion skin on all parts and leave 2" parameter on the edges for a better vac. Since we can run a fly cut on every nest, I just started doing that. Its cheaper that cutting trashed parts on the saw or recutting

Cabinetvision s2m, 40hp travini pump

9/26/16       #12: Time Per 3/4 ply sheet on CNC ...
Ken H. Member

Website: http://www.graybellmillwork.com

Mike,

I am curious what kind of spoil board material you are using. I only ask because I know that when were first getting started with our cnc, we tried using MDF for the spoil board instead of LDF (or MDFUL). There was no compairison. The LDF allows a lot more air flow and gives much better hold down.

With a nest like the one you are showing, you are going to be bleeding a lot of vacuum by the time it nears completion. You might try increasing the skin thickness to help keep the vacuum from escaping and keeping your spoil board surfaced regularly so you are not loosing so much around the edges.

We use the same Onsrud cutter as our main plywood cutting tool and typically run 800ipm with 18,000rpm. We don't run a lot of small part nests like you are running but we do have small toe kicks and stretchers in our nests and don't have issues with them moving as long as they are onion skinned.

9/27/16       #13: Time Per 3/4 ply sheet on CNC ...
Bill Member

I would use a 3/8 bit. We use a Vortex 3184XP on plywood.

We cut parts that are too small to cut on a CNC. Those parts always come with larger parts and we leave a skin between those parts. We have a flush trim router on the outfeed table of the cnc to zip them apart. Never fails.

You appear to have many similar small/thin parts. Can you join multiples and trim them apart after?

9/27/16       #14: Time Per 3/4 ply sheet on CNC ...
Mike M. Member

@ Ken H.

We do use standard MDF because we felt the LDF had too much vacuum leak. The problem we face is that we use a pusher off feed on a 5x12 bed, with that, putting cover sheets over the spoil board became tedious and we opted to slow down the bit while using regular mdf. We do have gasketed zoning and what happens with the LDF is that the vacuum leaks through the edges.

@ Bill

We do use onion skins for small parts but the problem with CV is that it doesn’t give me the option to leave the skin, it will always cut the skin off, risking the smaller parts at higher speeds. I’m going to experiment with tabs but the same problem exists.

9/27/16       #15: Time Per 3/4 ply sheet on CNC ...
B.H. Davis Member

Mike,

Are you saying you don't seal the edges of your spoil boards? That can have a big impact on holding power if it is the case.

BH Davis

9/27/16       #16: Time Per 3/4 ply sheet on CNC ...
Mike M. Member

@ B.H. Davis

We tried masking the edges with tapebut it wasn't a viable option when we had 12" of exposed spoil-board that was the real culprit.

However, I'm now considering sectioning my spoil-board into zones and sealing the edges in between.

We do a wide variety of operations on our machine, from cutting solid wood table tops to smaller solid wood parts to panel nests.

9/27/16       #17: Time Per 3/4 ply sheet on CNC ...
B.H. Davis Member

Mike,

We mostly do pod hold down on our CNC so don't do much spoil board work. As such we have 4 separate spoil board units (a Shopbot forum idea) that we mount to the MDF screw down table surface when we want to cut sheet stock. Four units at 24 x 48 each give us a 4x8 through vacuum fixturing surface.

When cutting parts smaller than the throw-on thru vacuum fixtures we use cardboard scraps to cover the open space. We have a lot around because we make our own boxes to ship our mouldings. It takes just seconds to cut a scrap to size to cover an open section of spoil board.

BH Davis

9/27/16       #18: Time Per 3/4 ply sheet on CNC ...
Ken H. Member

Mike,

By using the MDF you might not have as much loss on the edges, but you are also not getting enough vacuum where you need it, under the parts. By using MDF, you are not just sealing the open areas, you are also sealing the work area and drastically reducing your hold down power.

When we get our spoil board sheets, the first thing we do is paint all the edges to seal them (we use whatever latex paint we happen to have). We have a 5x12 table but typically only cut 4x8 sheets so we have gasketed off below the spoil board where it is not used. When cutting smaller parts than 4x8, we use pieces of 1/4" plywood to cover the open areas similar to B.H. Davis.

9/27/16       #19: Time Per 3/4 ply sheet on CNC ...
Mike M. Member

Based on your responses we're doing just that. Zoned SB, painted edges, LDF.

Thanks for the valuable input.

9/27/16       #20: Time Per 3/4 ply sheet on CNC ...
Mike

Not sure if this applies, but we have a 5x10 bed and mostly run 4x8 sheets. I took 2 pcs of laminate and glued them back to back to make panels that cover the unused portion of the bed,that along with CV stay down cutting have reduced my lost parts to almost 0. 18 hp becker pump with 3/4 ldf spoilboard and 1/4 ldf wasteboard.

9/27/16       #21: Time Per 3/4 ply sheet on CNC ...
cabinetmaker

"that along with CV stay down cutting have reduced my lost parts to almost 0. 18 hp becker pump with 3/4 ldf spoilboard and 1/4 ldf wasteboard."

Would you explain the CV stay down cutting is this in CV 9 or somewhere in S2M

We are running a 5x12 and use scraps to block offs 4x8's or the left over on the 8 foot length, anything you can share I certainly would appreciate.

9/27/16       #22: Time Per 3/4 ply sheet on CNC ...
Leland Thomasset  Member

Website: http://www.cnc-cabinetparts.com

stay down cutting is in both V8 and V9 of CV and you will find the settings in the s2m center under machine settings

10/1/16       #23: Time Per 3/4 ply sheet on CNC ...
cabinetmaker

Leland

Feeling a little lost I can't find it to save my life in 8 or 9 Could you post a screen shot

thanks

10/1/16       #24: Time Per 3/4 ply sheet on CNC ...
Leland Thomasset  Member

Website: http://www.cnc-cabinetparts.com

I will post a screen shoot for you shortly. sorry for the delayed response

10/5/16       #25: Time Per 3/4 ply sheet on CNC ...
Alex

You are already invested in your machine but from what i've experienced, roller hold -down CNC's are specifically made for frame cutting. Most companies with these machines even stack cut a few sheets in one shot. Any major cnc router manufacturer has roller hold-down as an option.


Post a Response
  • Notify me of responses to this thread
  • Subscribe to email updates on this Forum
  • To receive email notification of additions to this forum thread,
    enter your name and email address, and then click the
    "Keep Me Posted" button below.

    Please Note: If you have posted a message or response,
    do not submit this request ... you are already signed up
    to receive notification!

    Your Name:
    E-Mail Address:
    Enter the correct numbers into the field below:
     

    Date of your Birth:



    Return to top of page

    Buy & Sell Exchanges | Forums | Galleries | Site Map

    FORUM GUIDELINES: Please review the guidelines below before posting at WOODWEB's Interactive Message Boards (return to top)

  • WOODWEB is a professional industrial woodworking site. Hobbyist and homeowner woodworking questions are inappropriate.
  • Messages should be kept reasonably short and on topic, relating to the focus of the forum. Responses should relate to the original question.
  • A valid email return address must be included with each message.
  • Advertising is inappropriate. The only exceptions are the Classified Ads Exchange, Machinery Exchange, Lumber Exchange, and Job Opportunities and Services Exchange. When posting listings in these areas, review the posting instructions carefully.
  • Subject lines may be edited for length and clarity.
  • "Cross posting" is not permitted. Choose the best forum for your question, and post your question at one forum only.
  • Messages requesting private responses will be removed - Forums are designed to provide information and assistance for all of our visitors. Private response requests are appropriate at WOODWEB's Exchanges and Job Opportunities and Services.
  • Messages that accuse businesses or individuals of alleged negative actions or behavior are inappropriate since WOODWEB is unable to verify or substantiate the claims.
  • Posts with the intent of soliciting answers to surveys are not appropriate. Contact WOODWEB for more information on initiating a survey.
  • Excessive forum participation by an individual upsets the balance of a healthy forum atmosphere. Individuals who excessively post responses containing marginal content will be considered repeat forum abusers.
  • Responses that initiate or support inappropriate and off-topic discussion of general politics detract from the professional woodworking focus of WOODWEB, and will be removed.
  • Participants are encouraged to use their real name when posting. Intentionally using another persons name is prohibited, and posts of this nature will be removed at WOODWEB's discretion.
  • Comments, questions, or criticisms regarding Forum policies should be directed to WOODWEB's Systems Administrator
    (return to top).

    Carefully review your message before clicking on the "Send Message" button - you will not be able to revise the message once it has been sent.

    You will be notified of responses to the message(s) you posted via email. Be sure to enter your email address correctly.

    WOODWEB's forums are a highly regarded resource for professional woodworkers. Messages and responses that are crafted in a professional and civil manner strengthen this resource. Messages that do not reflect a professional tone reduce the value of our forums.

    Messages are inappropriate when their content: is deemed libelous in nature or is based on rumor, fails to meet basic standards of decorum, contains blatant advertising or inappropriate emphasis on self promotion (return to top).

    Libel:   Posts which defame an individual or organization, or employ a tone which can be viewed as malicious in nature. Words, pictures, or cartoons which expose a person or organization to public hatred, shame, disgrace, or ridicule, or induce an ill opinion of a person or organization, are libelous.

    Improper Decorum:   Posts which are profane, inciting, disrespectful or uncivil in tone, or maliciously worded. This also includes the venting of unsubstantiated opinions. Such messages do little to illuminate a given topic, and often have the opposite effect. Constructive criticism is acceptable (return to top).

    Advertising:   The purpose of WOODWEB Forums is to provide answers, not an advertising venue. Companies participating in a Forum discussion should provide specific answers to posted questions. WOODWEB suggests that businesses include an appropriately crafted signature in order to identify their company. A well meaning post that seems to be on-topic but contains a product reference may do your business more harm than good in the Forum environment. Forum users may perceive your references to specific products as unsolicited advertising (spam) and consciously avoid your web site or services. A well-crafted signature is an appropriate way to advertise your services that will not offend potential customers. Signatures should be limited to 4-6 lines, and may contain information that identifies the type of business you're in, your URL and email address (return to top).

    Repeated Forum Abuse: Forum participants who repeatedly fail to follow WOODWEB's Forum Guidelines may encounter difficulty when attempting to post messages.

    There are often situations when the original message asks for opinions: "What is the best widget for my type of shop?". To a certain extent, the person posting the message is responsible for including specific questions within the message. An open ended question (like the one above) invites responses that may read as sales pitches. WOODWEB suggests that companies responding to such a question provide detailed and substantive replies rather than responses that read as a one-sided product promotion. It has been WOODWEB's experience that substantive responses are held in higher regard by our readers (return to top).

    The staff of WOODWEB assume no responsibility for the accuracy, content, or outcome of any posting transmitted at WOODWEB's Message Boards. Participants should undertake the use of machinery, materials and methods discussed at WOODWEB's Message Boards after considerate evaluation, and at their own risk. WOODWEB reserves the right to delete any messages it deems inappropriate. (return to top)


  • Forum Posting Help
    Your Name The name you enter in this field will be the name that appears with your post or response (return to form).
    Your Website Personal or business website links must point to the author's website. Inappropriate links will be removed without notice, and at WOODWEB's sole discretion. WOODWEB reserves the right to delete any messages with links it deems inappropriate. (return to form)
    E-Mail Address Your e-mail address will not be publicly viewable. Forum participants will be able to contact you using a contact link (included with your post) that is substituted for your actual address. You must include a valid email address in this field. (return to form)
    Subject Subject may be edited for length and clarity. Subject lines should provide an indication of the content of your post. (return to form)
    Thread Related Link and Image Guidelines Thread Related Links posted at WOODWEB's Forums and Exchanges should point to locations that provide supporting information for the topic being discussed in the current message thread. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related Link that directs visitors to an area with inappropriate content will be removed. WOODWEB reserves the right to delete any messages with links or images it deems inappropriate. (return to form)
    Thread Related File Uploads Thread Related Files posted at WOODWEB's Forums and Exchanges should provide supporting information for the topic being discussed in the current message thread. Video Files: acceptable video formats are: .MOV .AVI .WMV .MPEG .MPG .MP4 (Image Upload Tips)   If you encounter any difficulty when uploading video files, E-mail WOODWEB for assistance. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related File that contains inappropriate content will be removed, and uploaded files that are not directly related to the message thread will be removed. WOODWEB reserves the right to delete any messages with links, files, or images it deems inappropriate. (return to form)