PCB engraved, what do you think about ? - Page 1
Forum section: electronics / general

author: legacy
author_rank: Super Contributor
timestamp: December 02, 2013, 12:47:57 pm
content: I am watching this PCB engraver, that's a common CNC design reduced in working size and simplified in order to get it cheap!CharacteristicQuoteSpecificationsQuoteworking flowit should be priced- 550 euro for the machine, assembled with (1) included- 150 euro for the shipping(1) included list1 X Sable-2015 CNC (frame and stepper motors, assembled)1 X 3-axis stepper motor driver1 X Switch power supply for driver3 X stepping motor connecting cable1 X spindle set1 X Switch power supply for spindle1 X ER11 collet (3.175 mm)1 X Spare belts1 X Installation and setup instructions

author: andtfoot
author_rank: Unknown
timestamp: December 02, 2013, 01:44:00 pm
content: As a concept it seems alright. The solid machine bed probably gives a good start to keeping the board flat, although you would need to bolt MDF or similar to the top anyway for drilling.I'm not a fan of the off-centre spindle motor mounting (although it's probably fine).The other thing is the lead screws. Standard thread is AFAIK pretty crap for this. I think it is prone to binding, wears out quickly, and usually has a fair amount of slop. ACME threads can fix this a little bit, but it's probably best to go to ballscrews if possible.The price doesn't seem much cheaper than the other CNC machines around. For example, a 300x200 machine with ballscrews for €518 + shipping:http://www.carving-cnc.com/3020series/cnc-3020z-d52-new-version-router-engraver-drilling-and-milling-machine.html

author: Kappes Buur
author_rank: Regular Contributor
timestamp: December 04, 2013, 06:54:02 am
content: Take a look atKroko's setup.

author: free_electron
author_rank: Super Contributor
timestamp: December 04, 2013, 08:08:34 pm
content: two questions :1) does it come with full licensed versions of all that software ? not pirated, not cracked but official and unlimited ?i see way too many of these machines that come with pirated versions of that control software. i dont; want to buy a 700$ machine and then have to find out i need to fork over another 500$ in software to get it legit...2) does it connect thru USB ? no computer has a parallel port anymore. parallel ports are gone, adieu , sayonara, goodbye. if it does not work over a USB link : fail. any 3d printer out there can already do it. why not these machines ?

author: Christopher
author_rank: Frequent Contributor
timestamp: December 04, 2013, 08:19:48 pm
content: LPKF ProtoMat machines are really nice, we have one at work. It gives great 8/8 results every time with careful setup.The only problem is changing the bits! And vias. Maybe I'm spoiled.

author: george graves
author_rank: Super Contributor
timestamp: December 04, 2013, 09:04:40 pm
content: Fiberglass dust is bad for you.

author: free_electron
author_rank: Super Contributor
timestamp: December 05, 2013, 01:10:10 am
content: Quote from: Christopher on December 04, 2013, 08:19:48 pmwe need two more icons... : Vomit icon and explosive diarrhea...Quoteyou need to handle it with gloves, ray to all the gods and godesses , hope the wind is good , it's the right time of day, season and whatever.if a butterfly flaps it's wings on the other side of the globe the board will faili have had a protomat 95S , a lamination press and the multicontac plating system. Never succeeded in making 1 working multilayer.

author: orion242
author_rank: Unknown
timestamp: December 05, 2013, 01:50:55 am
content: >explosive diarrhea...lol too funny!!I'm looking for a small CNC for PCB milling also. I would be interested in hearing from anyone with a working setup, or explosive horror stories of machines to avoid.

author: PlainName
author_rank: Super Contributor
timestamp: December 08, 2013, 01:21:07 am
content: I have and use a Sable for PCB milling. In my case I use a Proxxon IB/E as the spindle (has the spindle bearings mounted in metal) and it's good enough to manage 0.5mm pitch flatpacks and the like.I have a 1/2" perspex slab bolted to the work surface which I faced so it is flat and square. I stick the PCBs down with carpet tape (it is amazingly consistent in thickness, grips well, and you can get it off afterwards). That allows me to do the whole job in one go: drill the holes, mill the isolation, mill the board outline. Eventually the surface of the perspex gets pockmarked with tiny holes, so I just skim half a mm or so off the get rid of them when the tape doesn't stick any more.Dust control is via a car vacuum cleaner and 12V battery charger supply, linked to the spindle switch. Or it was - currently I am trying oil spread thinly over the entire PCB to lubricate the cutter, and that catches all the swarf. But the very fine powder dries out the oil and begins to look like a grinding paste, so I'm not sure it's a good thing to do...

author: orion242
author_rank: Unknown
timestamp: December 08, 2013, 01:31:34 am
content: What do you use to get from gerbers to g-code?

author: PlainName
author_rank: Super Contributor
timestamp: December 08, 2013, 02:12:46 am
content: Currently I used CopperCAM to generate the g-code paths, and Mach3 to do the actual milling. I think Eagle will generate g-code if asked nicely, but I've never used it so can't be definitive.I also use CutView for any milling job (PCB or 'real' milling) before letting letting Mach3 loose just to ensure I'm not about to make an expensive mistake

author: legacy
author_rank: Super Contributor
timestamp: December 09, 2013, 03:45:20 pm
content: thank you guys for these informations

author: denizcan
author_rank: Regular Contributor
timestamp: December 09, 2013, 08:44:06 pm
content: nice but what's the idea behind PCB milling? hobby? Positiv20 gives very sharp results on double side PCB's. also production quality PCB prototyping is super cheap and fast nowadays..

author: PlainName
author_rank: Super Contributor
timestamp: December 09, 2013, 10:14:01 pm
content: Quote from: denizcan on December 09, 2013, 08:44:06 pmCan't speak for anyone else, but for me it is fast and clean. If I etch then I have to get the tank of ferric out of the garage, heat it up in the kitchen, print the film, etc. Always a possibility of spillage and consequent explaining to the missus, and while that's going on no-one can make coffee or anything.With the mill there is no printing, exposing, or any of that stuff. All the holes are exactly aligned with the pads. An important factor is that the holes can be drilledbeforethe pads are produced, so there is less risk of the drill pulling off thing pads.Chinese PCB houses are indeed cheap and quick, but even they can't beat a mill for really quick - I have had an idea at 1am on a Sunday morning and got a working PCB before 2am. For the price of the cheapest copper clad board - no photo resist to go off or get scratched or add to the cost.I wouldn't sell the boards - they are for quick prototyping of ideas and one-off 'homers' that are suitable for the technology. Not all projects fit that scenario, but enough do to make the mill useful. Since I got the mill I've never etched a board - if it isn't suitable for milling it goes off to Itead and I wait 2-3 weeks for it to come back.Your Mileage May Vary. But we don't have to do either/or, you know. You could use a mill to drill the holes accurately and then cut out the PCB. Do that before exposing and it should be reasonably easy to line up the artwork with the holes, then expose and etch as normal. Voila - you no longer spend an hour straining your eyesight to drill the holes off-centre, and no need to make an allowance in the pad diameter. Slots easily, er, slotted. What more could you ask for?

author: orion242
author_rank: Unknown
timestamp: December 09, 2013, 10:20:38 pm
content: Hobby mainly, but I would think some of the reasons remain the same...I don't want to wait for a board only to find a mistake. If I can mill my own in a few hours, I'm days or weeks ahead of sending it out. I only have the weekends to piss around with hobbies, and bread boards are a real PITA for large circuits. Sticking circuits together on perf board is marginally better than breadboard... If I mill them, I'll be testing rev 4 by before I can outsource rev 1.Besides that I can use it engrave things, cut custom openings in project boxes, etc. It will probably lead into another project...building a CNC that can handle 4'x8' sheets...

author: orion242
author_rank: Unknown
timestamp: December 09, 2013, 10:21:12 pm
content: Ditto on etching.Been there done that. What a facking mess!!!

author: G0HZU
author_rank: Super Contributor
timestamp: December 09, 2013, 11:12:24 pm
content: Yes, milling boards is the way to goI bought a (used) T-Tech 7000S machine about 10 years ago for PCB design and it has been brilliant for making PCBs and also laminated tools and front panels etc etc. Mine is the larger machine and can mill a 19" x 13" PCB size.I design a lot of RF stuff up at many GHz using exotic PCB materials so a milling machine is essential for this kind of thing. I bought a second T-Tech 7000S for milling tougher tasks like laminated toolmaking because I want to keep the wear down on the original machine. These old T-Tech machines can be bought very cheaply nowadaysI use the LPKF CAM software to generate the isolation/rubout files and I use Isopro.exe to control the milling machine once the exported isolation files from the LPKF SW are imported. This is because the LPKF SW is far better than isopro when it comes to generating the isolation files.

author: G0HZU
author_rank: Super Contributor
timestamp: December 09, 2013, 11:26:29 pm
content: QuoteOne thing to be wary of with the old T-Tech machines like mine is that the working parts are very exposed and the motors produce a lot of torque and the moving top section is impossible (for me) to halt if I try to stop it physically. So if you caught a finger in the works it will probably chew it off without the machine even slowing down or groaning.I think the LPKF machines are a lot safer in this respect. We have one of these at my place of work. Don't expect perfect reliability from T-Tech or LPKF if you use it a lot. We have had both makes at work and both have required costly repair work more than once. However, our LPKF proto 60 machine has been a lot more reliable than the old T-Tech machines.The endmill and pointed and contour router tools aren't cheap and they don't last very long. I've been lucky in that I get to salvage the ones from the works LPKF machine once they pass a certain usage time so I have literally bagfuls of part worn tools to keep me going. But some of these tools are £16 each and they only do a few PCBs before they get flagged as worn out.

author: denizcan
author_rank: Regular Contributor
timestamp: December 10, 2013, 11:00:57 am
content: Quote from: dunkemhigh on December 09, 2013, 10:14:01 pmI see.. Is it precise enough for LQFP packages?

author: PlainName
author_rank: Super Contributor
timestamp: December 10, 2013, 08:54:57 pm
content: QuoteI reckon so. The photo is one I prepared earlier (and earlier enough that I'm not sure what the chip is - Ithinkit's an AVR).

author: G0HZU
author_rank: Super Contributor
timestamp: December 11, 2013, 12:58:42 am
content: QuoteWith care you can mill very fine detail.eg I have some flexi PCB material here that is 0.004" thick including the outer copper layers. It looks and feels like copper coloured paperOn my T-tech machine I can set the cut depth very finely and I've milled custom flexi cables to repair faulty cables using this material.

author: legacy
author_rank: Super Contributor
timestamp: December 12, 2013, 12:40:31 am
content: Quote from: G0HZU on December 11, 2013, 12:58:42 amexactly which machine is it ? is there in any catalog ? i'd like to buy one of these

author: PlainName
author_rank: Super Contributor
timestamp: December 12, 2013, 09:37:27 am
content: QuoteWow. Colour me seriously impressed

author: george graves
author_rank: Super Contributor
timestamp: December 12, 2013, 10:17:25 am
content: Quote from: dunkemhigh on December 10, 2013, 08:54:57 pmI'm impressed with the quality.But I'm in the toner etch camp. I can turn out a board in about 20 mins assuming it's SMD. TH takes about 2 seconds per hole, plus tool changes.

author: PlainName
author_rank: Super Contributor
timestamp: December 12, 2013, 10:34:05 am
content: It takes me 20 mins just to get the coffee onLast time I etched it took longer than that - printing the film, getting the kit out, exposing, developing, heating, etching, cleaning, etc. But I am happy to believe it really does take you 20 mins or less. For me, time is not of the essence so much as not having a mess (or potential mess) to deal with. And only one device to get going (vs lightbox, developer tray, etchant tank, cleaning tank/tap).But, as I said before, horses for courses and it is very much a personal choice. Sometimes I am tempted to use both (mill for drilling/routing and etch for fine tracks), but the scale of it overwhelms me

author: TheDirty
author_rank: Frequent Contributor
timestamp: December 12, 2013, 03:11:36 pm
content: I'm also able to etch very quickly, but it took me a while of experimentation to get to that point. Though I use the cheap Chinese PCB prototyping I still etch my own stuff for new chips or I just want to try something out. It doesn't make sense waiting a month to get 10 boards when you only need one and it would be useful to have it right now. I use toner transfer and there's no mess. I guess if I got really careless with the ferric chloride there could be a problem.I don't really have a point here, other than it can be done and it does have its down sides. If I had the money, sure I would get a routing table.

author: legacy
author_rank: Super Contributor
timestamp: December 12, 2013, 08:51:36 pm
content: what about the "tools" you use to engrave ? i mean what do you mont on your pcb-engraver in order to cut and drill ? and where do you buy it ?

author: legacy
author_rank: Super Contributor
timestamp: December 12, 2013, 08:53:10 pm
content: i am reading aboutthis, pretty news!

author: PaulAm
author_rank: Frequent Contributor
timestamp: December 12, 2013, 09:57:08 pm
content: QuoteHow cheap? Looks like one went on ebay for something under $2K US. That still seems pricey to me.

author: george graves
author_rank: Super Contributor
timestamp: December 12, 2013, 11:20:16 pm
content: Quote from: dunkemhigh on December 12, 2013, 10:34:05 amYea, with toner transfer, it cuts down on a lot of that exposing and developing.Print it, iron it, soak the paper, peal, and you're ready to etch. I use the hydrogen peroxide/HCl enchant....but I use hair salon peroxide(IIRC 20% peroxide), the reaction itself is exothermic, so no need to heat the chemicals. It's very quick. I can etch 10 square inches in about a min or two. I use copper fills on my boards where ever I can to reduce the amount of copper that needs to be etched. It makes life easier.Here's an example of how fast it can etch. I think his solution is a bit too strong!!!! But you get the point.For cleaning they get a quick bath of water and baking soda. Then a rinse and scrub under the tap. Finally, acetone to remove the toner, and a quick scrub with a 500 grit sand paper, or a scouring pad.I also use 1/32" boards where ever I can so that I can easily cut them with some metal shears.

author: edavid
author_rank: Super Contributor
timestamp: December 12, 2013, 11:34:05 pm
content: Quote from: dunkemhigh on December 08, 2013, 01:21:07 amDid you buy it from the same seller?Did it work out of the box?Did you try the Sable spindle, or start with the Proxxon?

author: PlainName
author_rank: Super Contributor
timestamp: December 13, 2013, 01:13:24 am
content: QuoteThe point I got was tray, bottles,gloves= mess.QuoteNever tried it, mostly because it's a total loss system. I tend to print to film and then keep the film so I can run another off without trying to make a good print again. [Sorry!Used to print...]Mind, it took me a lot of trial and error to find a happy combination of printer and film that would work perfectly every time. I think all of these things do, and once you've found what works for you it can be quite hard to realise it doesn't work for someone else, and they'll find some other method they'll swear by.

author: george graves
author_rank: Super Contributor
timestamp: December 13, 2013, 03:08:04 am
content: Quote from: dunkemhigh on December 13, 2013, 01:13:24 amNaw. I just use two small plastic tall containers. No spills, no mess. Disposiable gloves. It's not rocket science.Quote from: dunkemhigh on December 13, 2013, 01:13:24 am"Total loss system"? Uh, yes? One sheet of photo paper. Very wasteful.But to each their own!

author: orion242
author_rank: Unknown
timestamp: December 13, 2013, 08:25:11 pm
content: Quote from: george graves on December 12, 2013, 11:20:16 pmNever tried the toner method, always used transparencies and ferric chloride myself. Never did my mix, even heated, react like that witches brew… I think I would have added an apron and full blow eye protection working with that stuff (or ferric for that matter).What do you do to dispose of that stuff? Neutralize with baking soda and flush?

author: orion242
author_rank: Unknown
timestamp: December 13, 2013, 08:26:09 pm
content: Quote from: dunkemhigh on December 10, 2013, 08:54:57 pmNice! I'm sold...Now to convince the misses.

author: AndersAnd
author_rank: Frequent Contributor
timestamp: December 13, 2013, 08:29:28 pm
content: Quote from: orion242 on December 13, 2013, 08:26:09 pmWhile etching, just let her smell and inhale the acid fumes until she starts coughing, and say there's a way to avoid all this unhealthy acid.

author: orion242
author_rank: Unknown
timestamp: December 13, 2013, 08:36:45 pm
content: Or just dump the last of my ferric in the "stainless" steel kitchen sink....

author: PlainName
author_rank: Super Contributor
timestamp: December 13, 2013, 09:54:30 pm
content: Quote from: orion242 on December 13, 2013, 08:26:09 pmIt is easier to ask forgiveness than to seek permission

author: AndersAnd
author_rank: Frequent Contributor
timestamp: December 13, 2013, 10:15:29 pm
content: Quote from: dunkemhigh on December 13, 2013, 09:54:30 pmJust use it to engrave a necklace for her and you'll be forgiven.

author: george graves
author_rank: Super Contributor
timestamp: December 14, 2013, 02:11:08 am
content: Quote from: orion242 on December 13, 2013, 08:25:11 pmI neutralize it with baking soda(it changes color when it's fully neutralized)Then I let it sit, and the copper and salts will come out of solution and drop to the bottom. I then pour off the liquid (salt water) and dispose of it. I let the solid dry, and then put them into a container. Over the 7 years of etching 100's of boards, I only have about 1/2 of a gallon of solids. Eventually I'll drop it off at the dump when they have a hazardous material disposal day (along with a box of used AA/9V batteries)

author: legacy
author_rank: Super Contributor
timestamp: December 24, 2013, 01:04:16 pm
content: hi guyscould you suggest me a product and a seller?

author: PlainName
author_rank: Super Contributor
timestamp: December 24, 2013, 02:18:10 pm
content: Quote from: legacy on December 24, 2013, 01:04:16 pmA nice Uni-T meter, and perhaps some silicon leads with banana plugsQuoteFranky at iloveelectronics.

author: legacy
author_rank: Super Contributor
timestamp: February 28, 2014, 01:02:24 am
content: what do you think about thecirqoidmachine ?it could be bought incomplete packagewhich include- Cirqoid machine- Spindle add-on- Dispensing add-on- pick-and-place add-on- Drilling/milling spacer packalso available- PCB Insulation milling V tool - 0.2-0.5- PCB Insulation milling V tool - 0.1-0.15and provided with PCB laminate of 100x75mm or 100x160mm (combo kit available) area which is a bit small but, good enough for me

author: free_electron
author_rank: Super Contributor
timestamp: February 28, 2014, 01:10:23 am
content: more than 2000Euro for a simple 160x100mm work area ?25$ gets me 10 double side boards in china.. i can place 100 orders against this machine.

author: Harvs
author_rank: Super Contributor
timestamp: February 28, 2014, 05:13:23 am
content: Quote from: free_electron on December 04, 2013, 08:08:34 pmWhile I'm not in the pcb routing camp, to answer those questions specifically.Mach3 which is the most popular CNC software for those building their own machines (and I don't just mean hobbiests.) $175 for the full licence. However, I recon it's worth every penny. Where I work we have several machines, but are only used one at a time. We asked them if we needed to buy a licence for each machine (which we were fully prepared to do) and the answer was no, only one licence.As for USB. These cheap machines are probably parallel port controlled. But for $275 you can get a really great USB controller that takes all the pain out of kernel timing, generally allowing machines to run faster. Or you can go the route of an FPGA PCI card for similar money to achieve a similar result.

author: legacy
author_rank: Super Contributor
timestamp: February 28, 2014, 01:08:04 pm
content: Quote from: free_electron on February 28, 2014, 01:10:23 amit is not a simple machine, it is also adds- Spindle- Dispensing- pick-and-place- Drilling/milling spacer- Insulation millingbtw, could you suggest me a cheaper one ?

author: tjb1
author_rank: Regular Contributor
timestamp: February 28, 2014, 07:25:38 pm
content: Quote from: legacy on February 28, 2014, 01:08:04 pmYou can buy a Grizzly G0704 and convert it to CNC for less than that. Possibly do the same with a Bridgeport if you find one cheap enough.

author: granz
author_rank: Regular Contributor
timestamp: March 04, 2014, 08:00:45 pm
content: Quote from: tjb1 on February 28, 2014, 07:25:38 pmNo way you could do anything like PCB milling with a Grizzly G0704!The max spindle speed is like 2500 or something. Smaller bits <==> higher speed. Some people that have converted that type to CNC have added high-speed aux spindles for engraving etc.For an open-hardware option, the Shapeoko 2 looks promising. I'd take that over one of those Chinese machines, simply because of the much better community support.

author: G0HZU
author_rank: Super Contributor
timestamp: March 04, 2014, 09:06:46 pm
content: Quote from: PaulAm on December 12, 2013, 09:57:08 pmI paid about £850 for my T-Tech 7000S >10 years ago and it came with the Nilfisk extraction gear plus the full spares kit and plenty of tools. The original owner was HP and they only used it a few times.It was cheap because there was no £££ dongle with the Isolation/control software that ran it (lost?)That wasn't really a problem for me.I bought the second one a couple of years later for £600 but it had some motor/bearing damage due to misuse and this was reflected in the price. But it also came with spares and a Nilfisk extraction system. It had a dongle with it but I don't need the dongle.I've seen them on ebay for less than this in recent years but the risk is that you will get a sloppy or worn out one.The other issue is the availability of the old Isopro software that runs it. I'm not sure if T-Tech will release the older versions of Isopro. I haven't bothered to download/upgrade my Isopro control SW for many years now.

author: Harvs
author_rank: Super Contributor
timestamp: March 04, 2014, 10:42:10 pm
content: Quote from: G0HZU on March 04, 2014, 09:06:46 pmThat machine looks like it would be a piece of cake to switch over to Mach3, even if you have to replace all the electronics (stepper control) that's only ~$100 in total. Probably take a lazy afternoon to get it wired up and running correctly.

author: legacy
author_rank: Super Contributor
timestamp: November 15, 2014, 09:02:57 pm
content: any news, guys ?

author: legacy
author_rank: Super Contributor
timestamp: November 16, 2014, 12:24:45 am
content: i have bought & modifiedthisProxxon CNCmachine, it's cheap and good for my purposesi do not have money, but i love thesemachines, which are a lot of light years ahead

author: atferrari
author_rank: Frequent Contributor
timestamp: November 16, 2014, 01:29:36 am
content: Look for Stepcraft (at Iserlohn Germany).They only lack an automatic tool changer.There is even a kit to assemble yours as well.

author: legacy
author_rank: Super Contributor
timestamp: November 16, 2014, 02:17:11 am
content: is itthisone ?that's cool

author: atferrari
author_rank: Frequent Contributor
timestamp: November 16, 2014, 02:52:16 am
content: Quote from: legacy on November 16, 2014, 02:17:11 amYes. Three options (sizes).Peter Urban is a helpful person.

author: legacy
author_rank: Super Contributor
timestamp: November 16, 2014, 06:12:45 am
content: any direct experience about this machine ?also, which king of PCB Engraving Router-Tools do you suggest ?just to give an example, something likethese?(feel free to suggest a better place and tool to buy)

author: atferrari
author_rank: Frequent Contributor
timestamp: November 16, 2014, 11:05:18 am
content: Quote from: legacy on November 16, 2014, 06:12:45 amIf you ask to me, my sole experience is that for one day I failed to reach his place and buy it.He was involved in providing a kit, for quite long time, to modify a Proxxon 70 which included tool changer. (Google Usovo.de)What always worried me about all this is the uncertain necessity of maintaining / adhering to parallel ports and the like.Peter seems to have all that solved as well. Even software.

author: legacy
author_rank: Super Contributor
timestamp: November 17, 2014, 04:19:09 pm
content: who hasProxxon MF70+ kit, and used it as PCB engraved ?

author: Fred27
author_rank: Unknown
timestamp: November 17, 2014, 04:27:03 pm
content: Quote from: legacy on November 16, 2014, 12:24:45 amThat's my Instructable. I'm glad you found it useful.I've used that little Proxxon for PCB milling (and loads of other stuff) but now moved over to UV exposure. I found that the deeper contours of milled PCBs made dry film solder mask application more difficult.I'm tempted to move to a larger machine as the main downside to the MF70 is that it's tiny. It's surprisingly capable but has a very small work area, even after some extending it a bit.

author: legacy
author_rank: Super Contributor
timestamp: November 18, 2014, 10:25:55 pm
content: what do you think, guys, about?

author: legacy
author_rank: Super Contributor
timestamp: November 19, 2014, 07:53:28 am
content: do you think is really possible to do TQFP with a CNC ?which are the problems with an engraver ?

author: PlainName
author_rank: Super Contributor
timestamp: November 19, 2014, 12:45:41 pm
content: Quote from: legacy on November 19, 2014, 07:53:28 amYes, I've done LLGA28L, which is 0.6mm pitch.The issue with small stuff is not the width of the copper but the width of the gaps. The limit there is a combination of factors: the depth of the tool, angle of the tip, width of the tip, and runout. But these factors are, in turn, affected by other factors: the depth of the cut, for instance, is affected by squareness of the mill bed and flatness of the PCB.So whilst it is possible to do fine footprints, you can't expect to whip a new mill out of the box and run off that kind of job within half an hour. It can take quite a while to 'bed in' not just the mill and tool, but yourself, and you'll go through a phase where nothing happens as it should and you wonder why you are bothering with this rubbish. But ultimately you should end up with a good idea of the practical limits for your setup and, the important part, being able to consistently run off jobs within that limit.Note that all these videos show how this stuff works for the people making the videos, but your solution could well be different. For instance, just the matter of holding the PCB down has many solutions, and the one that works every time for me is carpet tape. However, the videos you post show a different method which plainly works for them. There is no right or wrong way, just what works for you, and it is the finding out what works for you that takes some time.

author: legacy
author_rank: Super Contributor
timestamp: November 19, 2014, 02:15:44 pm
content: understood, thank youwhich CNC& tools did you use for LLGA28L ?

author: PlainName
author_rank: Super Contributor
timestamp: November 19, 2014, 02:52:24 pm
content: I picked up a set of LPKF mills cheaply on Ebay. They are like normal mills (except very small and stubby), 60 degree and 4mil to 8mil, and I run 'em at a depth of 0.09mm.Due to runout the gap is actually wider than it should be, but it leaves enough copper for the pads to work and, since these would be prototypes, that's good enough for my purposes.However, I know someone who apparently uses the single edge pointed type of engraving cutter to achieve the same sort of thing. I have no idea how because that just doesn't work for me, but I've seen his impressive results. One thing we have in common is that we spread 3-in-1 across the PCB as a lubricant when doing the isolation milling. Before I did that my results were very variable and tools lasted hardly any time.