584,837 active members*
5,204 visitors online*
Register for free
Login
IndustryArena Forum > Other Machines > PCB milling > Which bits to use for PCB milling?
Page 2 of 10 1234
Results 21 to 40 of 186
  1. #21
    Join Date
    Jul 2012
    Posts
    89

    Re: Which bits to use for PCB milling?

    Hi Craig & Roger ... Hope things are well where you are ...

    @Craig: It would be helpful if you could find a reference to the Chinese company. Although I am a bit wary of using Chinese companies (it seems that they are often quite harsh on their employees and the environment) it would be very useful to know what to search for. So, if it is not too much of a hassle I'd appreciate this info ... BTW - can I ask you what you are making since you need so thick PCBs?

    @Roger: Hmmm, yes, the TIR .. As it is I reckon that my machine may be acceptable in this respect. However, the spindle motor is a Kress 6990E and I think that the basic construction should be fine. Also some time ago I found this ebay vendor offering to "align" any spindle down to 1um:

    https://www.ebay.de/itm/Hf-Spindel-F...p2047675.l2557 ... (Note that the text is in German but I reckon google translate could help)

    Conveniently he & also Rego-Fix are within Europe so maybe I can relatively easily update my spindle's precision.

    Cheers,

    Jesper

  2. #22
    Join Date
    Jun 2010
    Posts
    4252

    Re: Which bits to use for PCB milling?

    All true, but getting a BT30 spindle down to <10 um at the cutter shaft could be a slow and $$ exercise. If you do, we would love to hear all about it!
    Note: regrinding a spindle in situ on the CNC is a known service, but only part of the exercise.

    Cheers
    Roger

  3. #23
    Join Date
    Jul 2012
    Posts
    89

    Re: Which bits to use for PCB milling?

    >> All true, but getting a BT30 spindle down to <10 um at the cutter shaft could be a slow and $$ exercise. <<

    Hmmm ... Well, life has taught me some humbleness so I reckon you may be right about this ... So - and this is not relevant right now as I need to get other things going - but which not-too-expensive spindle would you suggest? I don't need a very powerful one but precision is key. What should I look for ... (I would prefer a non complicated spindle - i.e. no water cooling and not too noisy)?

    As it is I bought my current CNC as an allround CNC which I could also use to make parts for a new and more sturdy CNC if this need should arise ... But such a CNC likely would benefit from a better spindle.

    Cheers,

    Jesper

  4. #24
    Join Date
    Jun 2010
    Posts
    4252

    Re: Which bits to use for PCB milling?

    Sorry - I can't advise you about a new spindle as I have never replaced mine. I have stripped it down to the bearings for a full overhaul - the bearings are huge compared to some of the little 24k RPM spindles, and I have trammed it to within a few um.
    About all I can suggest is that a 'cheap' spindle will be quite expensive: you would have to buy it, and then buy a better one to get the machine to work. Extra expense and frustration.
    Me, cynic?
    Yup.

    Cheers
    Roger

  5. #25
    Join Date
    Jul 2012
    Posts
    89

    Re: Which bits to use for PCB milling?

    Hmmm ... ok, thanks for your feedback ... Just pondering

    Cheers,

    Jesper

  6. #26
    Join Date
    Jun 2010
    Posts
    4252

    Re: Which bits to use for PCB milling?

    That's the problem in this game: too many possibilities and not enough $$.

    Cheers
    Roger

  7. #27
    Join Date
    Jul 2012
    Posts
    89

    Re: Which bits to use for PCB milling?

    >> That's the problem in this game: too many possibilities and not enough $$. << ... Well, indeed. And IMHO (one?) of the most challenging disciplines here is to clearly define my needs so as to get the needed/desired machine. Not that easy not coming from the CNC world ....

  8. #28
    Join Date
    Jun 2010
    Posts
    4252

    Re: Which bits to use for PCB milling?

    At the risk of being legitimately accused of contradicting myself, thi is actually the only valid argument for buying a real cheap Chinese machine - IF you have the mech and electronic skills and tools to make the wretched thing work.

    After all those hassles you will have a far better idea of what you want - and you should be able to sell the Chinese machine locally as a going concern as well.

    Cheers
    Roger
    PS: no-one ever said CNC was a cheap hobby.

  9. #29
    Join Date
    Nov 2013
    Posts
    4280

    Re: Which bits to use for PCB milling?

    Hi Jesper,
    I've been through my email and deleted all of the junk. The companies name was Mentor, when they email again I'll forward you a copy.

    All of the routers use deep groove ball bearings. In order for them to spin 25000 rpm they must have quite a bit of clearance and consequently they
    'rattle'. I would expect TIR no better than 15-20um. Doesn't matter how good the collet is if the shaft has that much play.

    All high speed mill spindles have matched and paired (or multiple matched pairs) of P4 grade angular contact bearings, steel to about 24000 rpm, ceramic balls
    through to about 42000 rpm and ceramic balls and races beyond that. Above 60 000 rpm you are in air bearing territory.

    The manufacturer of my spindle claimed less than 5um TIR with the steel bearings fitted. It made sense then to get a good collet, the ordinary collet was about $15.00
    whereas the Rego-Fix one was about $30.00. Rego-Fix is the Swiss company that invented the ER collet system. Their toolholders are beautiful.

    I bought a Rego-Fix cylindrical ER25 toolholder from the New Zealand importer and it cost $460NZD, about $350US! I nearly died when I realized what I had committed
    myself to, on the other hand it is the core of my servo driven high torque spindle. The angular contact bearings are about the same money. I made this spindle myself,
    I couldn't afford to have it made for me and while its not perfect its not too bad either and it sure rips into steel and stainless. I'm quite proud of it and glad now that
    I elected to make it myself.

    The original purpose for the heavy copper board was for an AC servo drive board. The output is 15A per phase continuous and 48A overload. I'm using TO247 MOSFETs and needed
    fairly small width (3-4mm) traces to maintain the creep distance between traces thereby avoiding a flash over. As it turns out it is really nice to be able to use a traces as narrow
    as 1mm and still carry 10A. Once you get used to designing boards with that capacity you tend to become hooked on it and so I've made a few projects which are by no means
    as demanding as the servo drive but still take advantage of the heavy copper.

    Craig

  10. #30
    Join Date
    Nov 2013
    Posts
    4280

    Re: Which bits to use for PCB milling?

    Hi,
    this company:
    https://www.mechatron-gmbh.de/en/

    An I got this model...it was the cheapest:
    https://www.mechatron-gmbh.de/filead...FS-6508-AC.pdf

    This is the same size and power, 800W but watercooled and up to 60,000rpm with a 1000Hz VFD and look at the TIR<2um, probably cost a fortune:
    https://www.mechatron-gmbh.de/filead...FP-6508-60.pdf

    Craig

  11. #31
    Join Date
    Jun 2010
    Posts
    4252

    Re: Which bits to use for PCB milling?

    Nice unit, but only ER-11. Understandable for 24k rpm of course.
    I would love it, but sadly it would not handle my fly-cutter: 43 mm radius and a 12 mm shaft. Other cutters at 12 mm too. Usually spun at about 2,500 - 3300 rpm. VFDs have no power at those rpm. Can't have everything.

    Cheers
    Roger

  12. #32
    Join Date
    Jul 2012
    Posts
    89

    Re: Which bits to use for PCB milling?

    Hi all - or good morning as it is now here in Denmark ...

    @Craig: Thank you once more for describing what you are doing and giving various links. BTW I notice that you are also relatively new to this forum (22 posts) and so I reckon that most of your posts may have been in this thread - helping me out. Appreciated Craig

    >> I nearly died when I realized what I had committed myself to, on the other hand it is the core of my servo driven high torque spindle. << ... I just took a look at the ER series from Rego-fix, and yes, I would also have been surprised that it cost USD 360. On the other hand - have you ever been to Switzerland? To my memory Switzerland has the highest price index for living of any country in the world. I would expect this is reflected in the price level of the goods they manufacture. And then I assume there's shipping and customs to New Zealand (?)

    BTW maybe this ebay vendor is interesting to you:

    https://www.ebay.de/sch/heinle-zersp...p2047675.l2562

    About Mentor it would be fine if you can email me a copy of their promotional email when you get another one. The only Mentor I've found in China making PCBs is Mentor Graphics and they appear to have a couple of subsidiaries that do not describe in too much depth what they actually do:

    https://www.mentor.com/pcb/service-b...?country=China

    However, one possible advantage is that they appear to be part of Siemens so just maybe they have reasonable environmental and employee policies ...

    @blinkenlight: You gave me a couple of links in a previous post to companies within the EU who sell CNC mill bits. I have not yet thanked you for this - but thanks ... I have taken a look at them and will keep them in mind for future purchases.

    @RCaffin: >> Usually spun at about 2,500 - 3300 rpm. VFDs have no power at those rpm. Can't have everything. << ... Good to know that it may be so.

    Now off to milling - first aluminum milling today

    Cheers,

    Jesper

  13. #33
    Join Date
    Jul 2012
    Posts
    89

    Re: Which bits to use for PCB milling?

    Hi again ...

    Just wanted to briefly share the result of my first aluminum milling today. From looking at the picture (attached) of the milled aluminum I wouldn't exactly call it a success - BUT when using a 6 mm HSS steel end mill the end-to-end material thickness difference is less than 10 um - more like 5 um. Which IMH (and maybe uninformed ?) opinion is quite good - not least because the Z-axis for me also is the most important axis.

    That said I wonder if I can make you more experienced people look at the picture and say what you think is amiss here?

    * The milling trial to the far left was done with a 2.4mm "hartmetall" 2 flute end mill running at 24000 rpm and a feed rate XY of appr. 340 mm/min. The milling strategy is called "peel" and I think it looks worse on the picture than it actually feels when running my fingers over it.

    * The middle milling trial is with the 6mm HSS 2 flute end mill running at appr. 8700 rpm and 240 mm/min. Again "peel" strategy which appears to end the milling process with milling the sides of the area to be milled, thus creating a center-to-sides level difference.

    * The right-most milling ended before being completed because the milling process heated the aluminum which then released from the double-sided adhesive tape otherwise holding things in place. But this is where the mostly end-to-end Z-axis level difference is about 5um to 10 um.

    My impression of the mill while milling was that things were actually vibrating/shaking. And also that there was some XY-axis "chatter" which seemed to cause the grates on the sides of the milled tracks. This may of course be because I have used less than feasible end mills and less than feasible feed rates/spindle rpms, although I tried to adjust the spindle rpm up and down a bit during the millings. In any case I'd appreciate a couple of your suggestions for end mills (2-2.4 mm & 5-6mm) that I can use to face mill and 3D mill mainly smaller copper items - and wood items.

    Also - just out of curiosity - and if it's interesting to you! - do one of you have a link to a small CNC mill that will at least do aluminum perfectly - and also be ok/fine with steel and stainless? Could be interesting to see what is prioritized in such a design ...

    Have a good day wherever you are

    Jesper

  14. #34
    Join Date
    Jul 2012
    Posts
    89

    Re: Which bits to use for PCB milling?

    ... Well, not to elaborate too much on my own stuff but it seems that it is the Z-axis that is very "flexible" in the Y-axis direction (rotating "around" a Y-axis direction) ... ... Will have to find a work-around for this ...

    Cheers,

    Jesper

  15. #35
    Join Date
    Jun 2010
    Posts
    4252

    Re: Which bits to use for PCB milling?

    The photo:

    I suspect that the 6mm cutter may be too big for your router. Especially on the RH cut.
    I suspect that trying to do full-width cuts with that 6mm cutter is too much.
    I suspect that you need some lubricant on the cutter. If all else fails, try some WD-40, or even SAE-30 oil.
    I also suspect you need sharper (and new) cutters optimised for aluminium. Chinese carbide is not always 'sharp'.

    It may also be that you are trying to machine soft gummy bending-quality Al - which is rarely successful at the start.

    HTH
    Cheers
    Roger

  16. #36
    Join Date
    Nov 2013
    Posts
    4280

    Re: Which bits to use for PCB milling?

    Hi Jesper,
    Rego-Fix is expensive not only because its Swiss but its also superbly made and you pay for quality no matter from where.

    The Ebay listing shows a toolholder very similar to the one I used for about 130 EURO. The price I paid in New Zealand dollars is somwewhat inflated by virtue of going
    to the New Zealand importer but not hugely so. I would do some more research were I to consider another purchase like that.

    Craig

  17. #37
    Join Date
    Nov 2013
    Posts
    4280

    Re: Which bits to use for PCB milling?

    Hi Jesper,
    I agree with Roger, 6mm is too big for your machine, its just not rigid enough to contain the cutting forces.

    I would expect surface speeds of 200-500 m/min for good , sharp carbide.

    You will have to halve that (100-250 m/min) for HSS.

    Download a demo of HSMAdvisor.

    I would be using flood cooling, it improves the cut quality. Note that Roger is very keen on MQL and his description of it suggests comparable results.

    do one of you have a link to a small CNC mill that will at least do aluminum perfectly - and also be ok/fine with steel and stainless?
    Many a small, even Chinese, can do aluminum pretty well. Steel and stainless are A WHOLE DIFFERENT GAME AGAIN. The rigidity required for steel is
    an order of magnitude better than a machine that can do aluminum.

    You may note that I have two spindles, the 24000 750W one I linked to. I had hoped that I could do steel with it as well.....WRONG!!! I had to learn the hard
    way, cutting steel requires a high torque and slower speed spindle with a very rigid machine with high levels of thrust to cause the tool to bite into the material
    and resist the counter forces.

    Ergo I made my second spindle, 6.2Nm, 3500 rpm with a ER25 toolholder and a 1.8 kW Allen Bradley AC servo. It works well. Despite my machine being all cast
    iron and steel I could wish for still more rigidity.

    Craig

  18. #38
    Join Date
    Jul 2012
    Posts
    89

    Re: Which bits to use for PCB milling?

    Hi Roger ...

    & many thanks for your feedback. It is indeed helpful to get some experienced "eyes" to take a look and make suggestions

    >> I suspect that the 6mm cutter may be too big for your router. Especially on the RH cut. << ... RH means "right horisontal"... ? ... About the cutter: Would you say that a 4mm cutter would be more suitable?

    >> I suspect that you need some lubricant on the cutter. If all else fails, try some WD-40, or even SAE-30 oil. << I have some motor oil for my car which I can see is SAE-30. Will try this.

    >> I also suspect you need sharper (and new) cutters optimised for aluminium. Chinese carbide is not always 'sharp'. << ... As it is I will be cutting both aluminum & copper but from speaking with a cutting tool manufacturer here in Denmark I understand that the same cutters can be used for both materials. Apparently they pose similar challenges to the cutter ... Would something like this cutter be appropriate:

    End-mills 2-flute Short 1.5D - OSG WXL 1.5D - End mills, Drills - FrezyCNC.eu .... There's a 4mm, 6mm shank cutter a bit down the page.

    BTW I like your saying "I suspect" ... I would say it is a subtle & diplomatic way of trying to diagnose something from the other side of the world

    Cheers,

    Jesper

    P.S.: There's a CNC workshop not too long from where I live (25 kms - far in Denmark but I reckon just around the corner in Australia ... ) and he has offered to buy tools for me. I will ask him tomorrow if he has a suggestion/a cutter that I can buy from him (4mm?) ...

  19. #39
    Join Date
    Nov 2013
    Posts
    4280

    Re: Which bits to use for PCB milling?

    Hi,
    those OSG tools are expensive, OSG is good but those prices are over the top.

    Try drillman1....much better value and nothing shabby about Kyocera Tycom:
    https://www.ebay.com/str/CARBIDE-PLU...p2047675.l2563

    Craig

  20. #40
    Join Date
    Nov 2013
    Posts
    4280

    Re: Which bits to use for PCB milling?

    Hi Jesper,
    just saw this, NSK is very good:

    High speed spindle with controller unit

    Craig

Page 2 of 10 1234

Similar Threads

  1. Milling bits
    By genesiospinola in forum Community Club House
    Replies: 0
    Last Post: 08-01-2013, 12:47 PM
  2. CNC Milling Bits
    By continentaldia in forum News Announcements
    Replies: 0
    Last Post: 07-09-2012, 07:25 AM
  3. milling bits
    By pauley in forum Want To Buy...Need help!
    Replies: 0
    Last Post: 07-05-2012, 01:46 PM
  4. PCB Milling bits
    By reiyuki in forum PCB milling
    Replies: 6
    Last Post: 09-14-2008, 06:31 PM
  5. milling bits
    By pike88 in forum WoodWorking Topics
    Replies: 4
    Last Post: 09-24-2007, 06:02 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •