Isolation Routing PCBs

[cropwell]

This was my yesterday project ---
26017

and I briefly mentioned it in another thread.

Doddy - I cut the PCB with a 1mm single flute mill to drill the holes and clear the bulk of the copper, then tidied up the tracks with an engraving cutter, DOC 0.2mm.

The circuit was designed by an adaptation of one I found on t'Interweb. It is a logic indicator (Hi-Lo-Pulse) which used a 4001 quad NOR gate. I rejigged it to use a 4011 quad NAND gate as I could find some of those (I have probably also got a tube of 4001's somewhere in my entropy driven storage area).

The circuit was drawn up using Circuit Wizard (which is old and has a very basic component library) and that produced the circuit board and output Gerber and Drilling files.
26018
26019

I then used CopperCAM to build a dxf from the Gerbers and then I put the dxf through the CAM process to give Gcode.

This was all a small run as I want to do a larger board for my next(ish) project, but I will be starting with KiCAD for the circuit design.

[magicniner]

Technical question here -

Is an "Entropy Driven Storage Are" a big pile of stuff? :D

[cropwell]

Technical question here -

Is an "Entropy Driven Storage Are" a big pile of stuff? :D

..... and it is gravity powered.

Sorry Nick, I know that you are not technically minded :barbershop_quartet_ It is a shitheap, mainly on the floor.

[Kitwn]

"Entropy Driven Storage Area". Sounds like my brain. Though there are occasions when "It is a shitheap, mainly on the floor" fits as well!

I've been successfully using the toner transfer method for PCBs for some years. I prefer surface mount components myself (easier than drilling all those exactly spaced holes) where the spacing between tracks can be only 0.6mm for SOIC chips. Have you any experience of cutting PCBs for SMD components? I'd be interested to see how the two methods compare.

Kit

[cropwell]

I avoid SMD, I am not into that sort of thing.

Now that I am in my 70's my dexterity isn't good enough for placing and soldering SMD's.

In my younger days, before I had a CNC machine, I tried various etch mask methods with variable success. In fact I have probably still got the letraset type PCB transfer symbols in a file somewhere, but I doubt if they will stick now, they hardly did when they were fresh.

[A_Camera]

Nice work. Personally I don't remove the unneeded copper and prefer to create earth plane. It means less milling work. I also use a miniature table saw for cutting the PCB to reduce the CNC work even more. Previously I used Eagle but then my son didn't like Eagle because it is far too complicated to use if you are a newbie, so he found EasyEDA (https://easyeda.com/) when he wanted to make some PCB artwork, and after having tried it out about a year or two ago I got stuck to that one. It's web based, so I can access it anywhere I am, very fast, fairly easy to use and to create your own parts, as well as to generate tracks with the locally installed auto router. It has all the necessary functions and it creates g-code as well.

[A_Camera]

I've been successfully using the toner transfer method for PCBs for some years. I prefer surface mount components myself (easier than drilling all those exactly spaced holes) where the spacing between tracks can be only 0.6mm for SOIC chips. Have you any experience of cutting PCBs for SMD components? I'd be interested to see how the two methods compare.

Kit

I enjoy NOT having to deal with chemicals any more. In my opinion, it is just as fast to mill than to etch, if you take all the parameters into account. I have done a few surface mount PCB but prefer hole mounted parts. It's simply easier to handle and also to read the values and correct mistakes in design.

Drilling is really a non-issue, that's done accurately by the CNC, so it really doesn't matter. What is important is that the job can be restarted and repeated from the start because it does happen that the dill snaps and some times I don't see that before the job is done. This is especially the case with 0.6mm drills, I find them very easy to snap.

Anyway, SOIC is just fine but you need a good CNC with high enough accuracy and repeatability.

[cropwell]

Nice work. Personally I don't remove the unneeded copper and prefer to create earth plane. It means less milling work. I also use a miniature table saw for cutting the PCB to reduce the CNC work even more. Previously I used Eagle but then my son didn't like Eagle because it is far too complicated to use if you are a newbie, so he found EasyEDA (https://easyeda.com/) when he wanted to make some PCB artwork, and after having tried it out about a year or two ago I got stuck to that one. It's web based, so I can access it anywhere I am, very fast, fairly easy to use and to create your own parts, as well as to generate tracks with the locally installed auto router. It has all the necessary functions and it creates g-code as well.

I don't always remove the copper earth plane, it depends on the proximity to the tracks and where I have to solder. I use Circuit Wizard, which is now not supported and is an old and creaky product and does not support surface mount components anyway. I find the circuit simulation good for a quick indication that I have got it right, although it doesn't handle floating logic inputs very well. It does allow me to juggle the component placing before routing the nets. The Gerber and drilling files it produces go into CopperCAM, again an unsupported program I have had yonks. This defines the tracks and can produce Gcode directly with earth plane copper removal if desired, but I prefer to output a dxf and control gcode production with EstlCAM. I can also introduce custom board outlines at this stage.

It is not the latest whizzy whizzy method, but it works for me and it is software I am familiar with.

[cropwell]

"Entropy Driven Storage Area". Sounds like my brain. Though there are occasions when "It is a shitheap, mainly on the floor" fits as well!

I've been successfully using the toner transfer method for PCBs for some years. I prefer surface mount components myself (easier than drilling all those exactly spaced holes) where the spacing between tracks can be only 0.6mm for SOIC chips. Have you any experience of cutting PCBs for SMD components? I'd be interested to see how the two methods compare.

Kit

I used to etch boards and find the chemical etching dirty and dangerous and you have the spent chemicals to dispose of. Then you have to accurately drill ! Nah! CNC for me !

[Doddy]

but it works for me and it is software I am familiar with.

That's all you need.

(though Eagle IS better :nevreness: )

[cropwell]

That's all you need.

(though Eagle IS better :nevreness: )

You're proba bubbly right, and if I were starting from scratch I might go there. My next venture is to look at KiCAD ('cos I need to do some Arduino based circuits) when I have the mind space, but I am up to my neck in minor problems to sort out, including why my limits switches have just decided to stop fecking working and why the downstairs toilet light doesn't come on...........

Back to topic:- I have looked at Design Spark and Circuit Maker and both are difficult to use. CM is especially Nerd! So KiCAD next.

[magicniner]

I used to etch boards and find the chemical etching dirty and dangerous and you have the spent chemicals to dispose of.

It was great fun though! I remember building my UVA light box (pre-internet search engines) with a home brewed electronic timer and ink jet printing circuits on transparency. All info had to come from books, magazines and parts and consumable suppliers :D

[Doddy]

but I am up to my neck in minor problems to sort out, including why my limits switches have just decided to stop fecking working and why the downstairs toilet light doesn't come on...........


Limit switches?, had same with my home switches recently - turned out the supply to the NPN proximity switches was disconnected and the system failed silent. Bad design that I need to get around to fixing (nothing more fun than stalling your Z axis and bending the limit switch out of the way).

Downstairs toilet light... also had this fairly recently and ignored the fused spur plate above head height in the bathroom and rewired around it in the cavity. Then saw the plate and did the Homer ("Doh!"),

[cropwell]

It was great fun though! I remember building my UVA light box (pre-internet search engines) with a home brewed electronic timer and ink jet printing circuits on transparency. All info had to come from books, magazines and parts and consumable suppliers :D

The good old days when you could just pop to Maplins for a resistor and couldn't wait for Practical Electronics or Elektor to drop through the letterbox. Before that it was red spot and white spot transistors, just can't remember which was PNP and which NPN.

[cropwell]

Limit switches?, had same with my home switches recently - turned out the supply to the NPN proximity switches was disconnected and the system failed silent. Bad design that I need to get around to fixing (nothing more fun than stalling your Z axis and bending the limit switch out of the way).

26061

I think I may have found the Limits switch problem, when I put a larger cable chain I did not route the Z axis homes and limits cable properly and it was being pulled along the X axis. .
I am going to remake the bracketry when I get my 3D printer working again (waiting for X axis motor cable). It just seems that disconnects in moving cables are blighting my life at the moment).

I need to get back onto PCB cutting !!!

[ericks]

Good job:)

[Kitwn]

It was great fun though! I remember building my UVA light box (pre-internet search engines) with a home brewed electronic timer and ink jet printing circuits on transparency. All info had to come from books, magazines and parts and consumable suppliers :D

Eeeeee lad, I remember those days! The Maplin catalogue and sending off hand filled in order forms by post, Practical Wireless, The Radio Constructor and Veroboard. In those days I drew brain-designed PCB layouts on 0.1 inch graph paper and then transferred the holes to copper board with a pin and drew in the traces using what Maplin sold as a special PCB resist pen but was actually a bog standard permanent marker, just three times the price. I even had my own personalised call sign, G0KIT. Nostalgia's not what it used to be!

More seriously, I've recently changed from using Eagle, where I never quite mastered the libraries and creating new footprints for the PCB, to DipTrace which is a bit easier to use and does have a free-for-non-commercial-use version if you look carefully enough at the website. I've only made one board with it so far but I like it so far.

As for etching, you can use remarkably little fluid by wiping it over the board with a sponge or cloth. A bit tedious but it doesn't take that long and I don't make enough boards to worry about the time.

I'm not sure my current CNC router is precise enough for milling a decent PCB. There's only one way to find out though and it would be a good test of my design and build skills. Off down another rabbit hole!

Kit

[Clive S]

And how about the XFG1 gas filled triode valve that was used in radio control receivers and mighty midget motors. :yahoo:

[Kitwn]

And how about the XFG1 gas filled triode valve that was used in radio control receivers and mighty midget motors. :yahoo:

I never got into valves until I turned from a radio amateur to a radio professional. Then I had BY1144 water cooled triodes to play with!

[cropwell]

I'm not sure my current CNC router is precise enough for milling a decent PCB. There's only one way to find out though and it would be a good test of my design and build skills. Off down another rabbit hole!
Kit

One of my biggest problems was getting the machine bed level. It is fairly good now as one side is hoiked up with brass sheet and aluminium foil to shim it level. Before that I used to cut the outline of the board and then put the board in a board-shaped pocket with some thin double sided tape. I still mill out a pocket (in the spoil board of course!) this levels up enough to get a consistent depth of cut.

Never been into radio, and the nearest to valves I have been was when I built a 15W(?) amp from a kit. It had EL84's as output stage an ECC83 phase splitter and I think ECC83's for preamp, but that was nearly 60 years ago and I haven't touched a valve since.

Rob-T

[Kitwn]

There is software out there that will probe the surface of your uncut PCB (obviously with the aid of a suitable probe mounted on the Z axis) and then modify the G-code to make the tool follow the measured undulations. I think this is the sort of refinement that might be needed for SMD boards , though a machined flat base and double-sided tape is more my kind of technology.

I have enough unfinished projects at the moment so a new way of making one or two circuit boards per year is going to stay firmly OFF the ToDo list for now.

Kit

[magicniner]

I used a Roland engraving spindle with a surface following nose on a sprung carrier for micrometer adjustable fixed depth engraving on uneven surfaces.
The engraving spindle was belt driven from the main spindle and gives 30000rpm from a 5000rpm main spindle speed.
I need to build a new unit for my new CNC though as I sold the high speed spindle arrangement with the old mill.

[cropwell]

More seriously, I've recently changed from using Eagle, where I never quite mastered the libraries and creating new footprints for the PCB, to DipTrace which is a bit easier to use and does have a free-for-non-commercial-use version if you look carefully enough at the website. I've only made one board with it so far but I like it so far.
Kit

I tried out Dip Trace last night after getting nowhere with KiCAD. Within an hour or so I had learned enough to create a schematic
26078

and this morning create the Gerber and drill files to manipulate with CopperCAM to give me the Gcode to make the board.

All I need now is the machine back together to cut the board.

Cheers,

Rob-T

[Kitwn]

Within an hour or so I had learned enough to create a schematic...... and this morning create the Gerber and drill files to manipulate with CopperCAM to give me the Gcode to make the board.


Blimey Rob, you're clever! Are you going to write a tutorial?

Kit

[cropwell]

Blimey Rob, you're clever! Are you going to write a tutorial?

Kit

It is not down to clever - Dip Trace is quite easy and there are online tutorials. So for me it was 'Monkey see, Monkey do'. Once I got to the Gerbers then CopperCAM did the conversion to dxf and then Estlcam to Gcode.

Do you really live in Exmouth on the North West Cape ?

Cheers,
Rob-T
btw I am fed up with the hot weather, I am having to empty the water bucket on the air conditioner (in my office) every day at the moment.

[Kitwn]

Rob,
I found DipTrace quite easy to use as well. I've never got into gerber files for drilling etc. but that would be a sensible thing to learn about even if I still use the toner-transfer method for making the boards, it would be nice to print some registration marks and have the CNC router drill the holes in exactly the right places. I need to make a new board for my GPS/crystal locked wooden clock so that might be something to experiment with.

I do indeed live on the cape in Exmouth. We're a bit remote up here. It's the same distance from here to Perth, the state capital, as from Land's End to John'O'Groats but there's only two sets of traffic lights in the first 13 hours driving.

It's really funny watching pommies complaining about the heat. We're enjoying similar temperatures as part of our nice, cool winter here, though we have had a bit of rain in among the clear blue skies and daily maxima of a comfortable 26-28 degrees. We've even had to put the duvet on the bed this month! For most of the year the overnight low is over 20C. I always tell people that January here is like January in England...Everybody hides indoors and burns tons of electricity to change the temperature. We had weeks on end of well over 40 earlier in the year which is really draining, I sooooooo enjoyed a trip back to Blighty in February when I could enjoy walking around london in sunshine and 16 degrees. I wore long trousers, shoes with socks in, a nice shirt that wasn't soaking wet and even a blazer with pockets for my phone and wallet! Air-con is essential here both in the house and the car, I doubt you can buy a car in Australia without it now and every building is cooled, including my shed.

Kit

[A_Camera]

Eeeeee lad, I remember those days! The Maplin catalogue and sending off hand filled in order forms by post, Practical Wireless, The Radio Constructor and Veroboard. In those days I drew brain-designed PCB layouts on 0.1 inch graph paper and then transferred the holes to copper board with a pin and drew in the traces using what Maplin sold as a special PCB resist pen but was actually a bog standard permanent marker, just three times the price. I even had my own personalised call sign, G0KIT. Nostalgia's not what it used to be!

Elektor was my favourite.


More seriously, I've recently changed from using Eagle, where I never quite mastered the libraries and creating new footprints for the PCB, to DipTrace which is a bit easier to use and does have a free-for-non-commercial-use version if you look carefully enough at the website. I've only made one board with it so far but I like it so far.



You should try EasyEDA. It is very simple to create new parts, edit the millions of available ones or create/change footprints. The only thing I am missing is auto placing the parts when creating PCB.

[Neale]

I've been looking at getting some suitable cutters to have a go at this myself - had a project or two in mind that haven't been started because I haven't decided how to make the PCBs. With auto-levelling software available, though, CNC machining looks viable with my machine.

I'm a bit confused about cutter choice, though. I see "PCB drill/mill" listed on eBay (although they look like milling cutters to me), or V-bit engraving cutters. Cropwell mentions using both, and then there's a wide range of diameters. Could someone recommend a good starting point for making, say, a PCB suitable for 0.1 pin spacing DIL packages (no SMD!)?

[Doddy]

My own experience, 0.3mm end mills have much better performance than v cutters, but then my v cutters were cheap Chinese jobs. The V cutters always seemed to tear at the copper a lot more than end mill, but I was trying to get to small geometry tracks (12 thoa, etc)

I think much of my frustration was developed early on with the Marchand Dice machine. Maybe I need to give my starmill more of a role than drilling uv etched boards. Pretty much any board I make now though is just for debugging before I throw $5 into dirtypcb for them to professionally make 10-off (and me wait 8 weeks)

[Doddy]

Oh, any pcb endmill with a cutter length more than 2mm isn’t going to last longer than a pingfuckit

[Doddy]

I’d also caution to understand how much grief you’re prepared to put up with. I can go from print to board with the usual uv processes within an hour and that includes 10 thoa routing and 0.5mm pitch SSOP devices with 80% success (and likely reworkable failures). The quality surpasses anything I’ve milled myself. You experience may vary, of course

[Doddy]

Last post, I promise!

Of course isolation routing opens the possibility of through hole plating... something else I promised myself to try.

I really need to get back on the horse with this one.

[cropwell]

As far as cutters are concerned, I use a V cutter of 0.2 mm end diameter. I have ordered some 10deg ones from China, but so far they have sent me 30deg ones twice ! The narrower angle ones have better control of track width.

For drills, I buy from circuit2u.co.uk £6.99 for a pack of 10. They are resharpened ones, but good and sharp. For normal components I use 0.8mm, but headers and connectors need a slightly bigger diameter, so 1mm. Actually, if the pads are large enough, I just drill the lot at 1mm.

Doddy, I understand your frustration, I have one of those F-awful machines from Exeter. I have spent a lot of time aligning it, even to the extent of shimming the bed with layers of kitchen foil. It now gives acceptable results, but I am still not sure the spindle is at 90deg to the bed as a cut with a large cutter produces a very 'steppy' result. I think the rails are twisted relative to each other. This is because of the inaccuracy in manufacture.

I used to use 0.2mm endmills, but those little feckers would break if you looked at them funny. Like the 'pingfuckit', I have a box of them with more on the floor.

Happy Days,

Rob