CNC

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

CNC bit Chipping

7/12/16       
Bob

I have some trouble with 5/16 bit.
Somehow this bit is making cut which is chipped and clean when making dado cuts . That clean cut looks like it is for male dado, chipped cut looks like for female dado.
I am sending picture when it shows that some dados have clean cut and the rest of them is terrible chipping . It is the same bit.
Any idea what is happening ?


View higher quality, full size image (2592 X 1944)

7/13/16       #2: CNC bit Chipping ...
Mike

If you have been reading posts here before, you should know that you need to provide more information. What kind of bit? Up spiral, down spiral, or straight. How many flutes? Feed and speed data. Did you ramp in the cut, or plunge vertically? Single pass? Just guessing, without any important information, it looks like a plunge cut, single pass where the two cleanest cuts were first and second in order. Rpm's too high, feed too slow so the bit got hot and chipped out the remaining cuts. That is only a guess. Another possibility is poor quality core on the board is contributing to the problem.

7/13/16       #3: CNC bit Chipping ...
Jerry Member

Are both cuts going in the same direction. One looks like it is packing the chips in front of the cut and the other looks like the chips are behind

7/13/16       #4: CNC bit Chipping ...
Brad

As asked previously...

1. What type of bit? Up Shear, Down Shear, Compression, Straight?
2. Are the depths of the dadoes all the same?

7/13/16       #5: CNC bit Chipping ...
Brad

...if using a Compress bit and the depth are NOT the same then -

The shallower cut would be exposing the Up Shear section of the tool to the top melamine surfece, whereas the deeper dado would bury the Up Shear section and the Down Shear part of the cutting edge would leave you with a clean, non-chipping finish.

(Could not tell conclusively from the image, but depth could be different.)

BTW: What is the difference between a Male and Female Dado?

7/13/16       #6: CNC bit Chipping ...
Bob

This is 2 flute 5/16 down cut . dept should be the same .
Attached is picture of final product . Cut for male dado cut is clean and for female dado do chipping . Any idea ?


View higher quality, full size image (1632 X 1224)


View higher quality, full size image (1632 X 1224)


Click the link below to download the file included with this post.

2Full_page_photo.pdf

7/13/16       #8: CNC bit Chipping ...
Richard

Hi Bob,

I agree with Jerry it looks like for some reason the female grooves are being routed in a different direction to the males. Either that or in 2 passes. Watch carefully when it's cutting and see if it's making 2 passes & which direction it's cutting.

Good luck.

Richard

7/14/16       #9: CNC bit Chipping ...
Chuck Hicks Member

Bob,

What are the feeds and speeds you are running with this tool?

7/14/16       #10: CNC bit Chipping ...
Bob

Attached is picture of tool setup


View higher quality, full size image (496 X 573)

7/14/16       #11: CNC bit Chipping ...
Chuck Hicks Member

What percentage of the feed rate are you running?

7/14/16       #12: CNC bit Chipping ...
Bob

100% and i can set that just in material property

7/14/16       #13: CNC bit Chipping ...
Bob

here is screen shot of property


View higher quality, full size image (992 X 291)

7/15/16       #14: CNC bit Chipping ...
Jason Scott

your lowering speed seems really high. Could your bit have been damaged and just cut the dadoes after the tenons?

7/15/16       #15: CNC bit Chipping ...
Blaine

It appears that your part is not securely held.
By that I suspect the part is vibrating up and down. There is usually an unusual noise (pitch) change when the part is being cut, if this is happening.

Also, poor dust extraction can exacerbate this as well.

Blaine

7/15/16       #16: CNC bit Chipping ...
Bob

Hi Blaine
No there is not any vibrations . If you check picture you will see that is on same sheet clean cuts and chipped . CNC 5/16 bit make clean cut for tenons ( blind dado ) and chip so much on mortise ( blind dado )

7/15/16       #17: CNC bit Chipping ...
Blaine

Hi Bob.

Something else to look into, I noticed the cuts that are chipping are not parallel to X and Y, they are somewhat diagonal.

Try cutting parallel to X and Y, then try the diagonal cuts again. You may have some oscillation when the machine is interpolating the XY linear moves that is causing the chipping.

Blaine

7/15/16       #18: CNC bit Chipping ...
Bob

i check that ready .

7/18/16       #19: CNC bit Chipping ...
Blaine

Put in a new tool, and try this.

Try cutting a hexagon approximately 10" in diameter, clockwise.

On the same sheet in the same program, offset the the geometry 5" or so to allow good visibility of the cuts, use the same geometry in the opposite direction, counterclockwise.

Is there any difference in the amount of chipping, and where it occurs in the 2 hexagons?

Please post a picture.

Thanks,

Blaine

7/22/16       #20: CNC bit Chipping ...
Gary B.

post a picture of the bit....

7/23/16       #21: CNC bit Chipping ...
Jarvis

We just seen the same thing
I grabbed an old scrap pc of melamine and cut that and it dont do it so we determined that we got a bad unit of material


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)