@andrew Important to note, that I'm still talking about hobby cnc solutions. For professional CNC working and for a pro machine I'd prefer to use as many "pro" and automated solutions as possible.
for occasional hobby purposes defined in this thread, and for these damn cheap machines I think it does not make sense.
pro machines with auto tool change do benefit from auto probing, but that is a total different story.
@NeverDie : well,
when you need a single z touch levelling then better to have a rock solid solution rather then have additional moving parts and potential other vectors for a failure. even with a slow feed rate, a single probe can be done in an acceptable time period, so why should you risk your result?
I can imagine that this spring stuff can help you when you approaching with quite high feed rate for first, but in such case I would be afraid of the "wearing" of the probe surface over time and the inaccuracy it may cause later on.
btw, the "double probing" with fast then a slower feed rate is used by other sw/firmware, e.g. marlin does the same (in certain configurations) for 3d printers.
@NeverDie after changing the tool I always make a single touch probe so Z level can be adjusted to the new tool properly.
This is necessary even for the PCB milling. After the levelling is done, a single touch probe is needed somewhere in the working are to set the Z0 and to make it as a reference point for the bed levelling mesh.
At least this is how it is done in bCNC.
After the isolation routing is done, I make a single Z touch probe for each drill bits to set the correct Z0 for the given bit. This is done in the same way as in case for the PCB probing.
Note that as the drilling on Z axis does not require high precision (basically if your drilling depth is slightly bigger than the PCB thickness, then even if your Z is just roughly adjusted to the PCB top, it will do the job).
As I currently work with PCBs only, no other touch probe was necessary, however for woodworking (or for other non conductive materials) one can use a dedicated "touch probe".
There are nice solutions form a simple PCB:
DIY Z Probe For CNC Machine – 08:26
— Nikodem Bartnik
or
UPGRADE CNC 3018/ PRO Z-PROBE | Z Axis tool probe | GRBL | EASEL | SUB – 10:02
— Cosmo Channel
or you can buy a cheap touch probe as well:
https://www.aliexpress.com/item/4001010640247.html
or you can go for nicer and more expensive professional touch probes 
I had a chance (and a need) to make a quick PCB prototype again, so I've finished my first real-life exercise with my new CNC3020(T).
I made two mistakes:
Beside these issues, the result still looks amazing.
Here are some pictures for reference:
isolation:
CNC3020T PCB isolation routing – 00:17
— András Kabai
drilling:
CNC3020T PCB drilling – 00:42
— András Kabai
Conclusion: CNC2030T is an affordable CNC machine which can be easily used for precise PCB prototyping.
Btw, this was my conclusion for my previous CNC2418 as well. Both of them proved their capabilities. CNC3020T is just better, more robust and good for more stuff.
To be honest, if one buys a CNC from the super cheap 2418 category and the main goals is PCB milling/drilling, then I do not see any reason to spend money and time on upgrades, as the base machine is good for the job.
@andrew oh, for those who are interested, flatcam settings were the followings:
the engraving tip was 2001 (20degree, 0.1mm end)
quick update, just managed to make some test milling.
pro tip: always check your tip before milling I had to trash the one I used for the first two, as its end was chipped
traces are 6 mil, the footprint is tqfp100 p0.5, built in from kicad.
some of the the standalone traces are 6 mil with 6 mil clearance, their open end came up, but otherwise it looks ok.
other 6 mil traces that are connected to pads are actually ok.
6mil traces where the clearance is 4 mil only were not millet at all, due to the isolation routing path made by flatcam.
overall, I'm happy with it.
I've also ordered a dial indicator measurement tool, I'll report the backlash and other measured precision details when it arrives.
some pics:
the control box is open and it has an additional external grbl controller now, I'm working on a proper electronics.
@niallain it is 3020T which uses trapezoidal screws. "Z" uses ball screws.
you can check the "official" technical details on the item's specification (scroll down to the description then click on the "specification"):
...
Driving units X axis: 1204 trapezoidal screws
Driving units Y axis: 1204 trapezoidal screws
Driving units Z axis: 1204 trapezoidal screws
...
Repeat accuracy: 0.05mm
...
Spindle precision: radial beat acuities 0.03 mm
...
Note that none of these parameters above are confirmed. To be honest I don't have the right measurement tools for that, but the fine trace PCB samples will prove it, or not
@NeverDie it is a knob for manual positioning. the whole assembly and machine is very massive and stable, all metal parts do matter a lot.
@mlei30 This was my choice:
https://www.ebay.com/itm/CNC-Router-3020T-3-AXIS-USB-Graviermaschine-GraviergeräT-FräSmaschine/313030564524
It already arrived and I started to play with it.
I decided not use its Chinese controller software or Mach3 with parallel port connection, so it needs some upgrade before I can make the first tests with it.
There are tons of upgrade options to make it work with open source stuff. I almost ordered a TinyGv2 controller, but it turned out, that that CNC can be GRBL controlled over the parallel port. In such case,
original stepper and spindle drivers can be used as well.
The problem is, that the research I found behind this was misleading and it contains inaccurate / improper details (or at least not exactly applicable to my HW version), so I had to re-execute the reverse engineering.
I'm about to finish it. At the moment I can control everything on the CNC from GRBL. Now I need to calibrate it and make the solution "solid/proper". I have hard time finding free time for this, but I hope that first test runs will be done soon.
I'll be back with the results soon (and I'm also planning to write a blogpost on the details later).
@NeverDie sure, you will hear more about my new gear
Considering the shipping time and my availability, this should happen around late August or early September!
Hey @NeverDie, everyone,
It is good to see how this thread developed over the time and you guys are enjoying the PCB milling.
Unfortunately I had many other responsibilities and was super busy, so a lot from my projects had to be postponed. Nevertheless I'm still working with my CNC.
A few days ago I replaced the spindle to a laser module to make same plywood engraving, and the original spindle motor holder (the 3D printed stuff) broke during the unscrew...
I managed to fix the laser module with cable tie.
It is ok for the laser, but of course not for the spindle and for the PCB milling.
Replacement parts are available mostly in packages (e.g. https://www.ebay.com/itm/Replacement-Parts-DIY-Kit-for-CNC-1610-2418-3018-Spindle-Holder-Screw-Polish-Pod/112382449851), but it is possible to print your own version too.
Some guys already came up with an enhanced design, such as https://www.thingiverse.com/thing:3586273
I already wanted to make an upgrade on the CNC, so I came to a conclusion, that I will fix the broken part with a custom 3D printed one, then sell the machine.
I already ordered my new toy, a CNC3020T (EUR 325 + shipping EUR 25):
Well, I hesitated a lot and almost bought a CNC3040Z-DQ (bigger, better, ball screw), but as currently I really don't have enough space for it (and to be honest, no reason to buy a better/bigger) I sticked with the 3020T. The quality I achieved with my 2418 will be definitely reproducible and this is enough.
I just read the endmill isolation routing posts. Interesting stuff.
I'm curious whether you can use smaller ones to deal with the 6mil/6mil trace/isolation sizes.
Happy milling and cheers!
@lamikr pls see one of my very first test I made after I built my cnc. check the TQFP100 footprint.
for me, the cnc2418 was good choice. with proper assembly it is very stable and its output is stable.
I was using the cnc for designs down to 10mil traces without any issue.
so, I have good experience with my low cost cnc but do to the lack of hands-on experience with other devices, I cannot compare or recommend others.
@jeremushka I reused the top PCB (the touch panel) with its original microcontroller, but with a custom firmware. the bottom PCB was fully replaced with my own designed version. this includes the power supply with additional protections, atmega328, atsha and nrf radio.
it is running very well on my desk, but I was super busy in the past months so it is not yet installed to the wall.
in parallel I also had to finish its opposite side, the controller at the lamp. it is also ready for final installation, I just need time for that
@neverdie the controller does not limit it, but the firmware settings. however, based on my default settings the feedrate is limited (by config) to 800. check your $110, $111, and $112 config options.
https://github.com/gnea/grbl/wiki/Grbl-v1.1-Configuration#110-111-and-112--xyz-max-rate-mmmin
you are free to override this configuration with a different value, so you can try 1400 in the grbl firmware settings, which will cause real 1400 feed rate in case of you test G code.
the questions is that how the steppers/spindle could handle this.
@neverdie what was the cost for the overall upgrade?
for me the 10 mil traces also worked with the default sw/hw configuration.
did you change any parameter in the grbl firmware? 1400 feedrate is very nice, much faster than mine, however I did not use higher rates than 200 so far.
your steppers are still the same? is it ok for the high feedrate without any issue?
hello everyone,
what is the current status with the quality, fine traces and result stability?
after a long absence I finally had some time to finish my new board and prototype it.
I don't have those issues that appearing for some of you, the result is pretty nice, the milling quality is the same across the whole board.
in this design the thinnest traces were 15mils, and the smallest vias were 0.8mm with 0.3mm drilled holes.
just for reference, please see my relevant configuration options detailed below:
tools
config
software:
I just started to review the NRF5* possibilities. regarding to the code protection, are you sure that you have to implement this by your own?
what do you think about CTRL-AP - Control Access Port, APPROTECT?
@neverdie said in CNC PCB milling:
What's the best type of sacrifice board to use if doing bed flattening? Regular wood, or should I stick with particle board or MDF?
I never had to try it, so I don't know. for me the regular wood seems to be logical...
@neverdie for pcb milling a small height difference across the board's area could result in a big negative effect if autoleveling is not performed properly.
I would double check your autoleveling process, on the other hand, you could also try to use bed flattening with a bigger endmill tool first, then place the pcb to the flattened area. this could help you to eliminate or decrease the cnc assembly or the sacrificial board caused roughness.
for further details please see the following link:
http://flatcam.org/manual/procedures.html#bed-flattening
@neverdie said in CNC PCB milling:
I drilled the alignment holes with 0.8mm diameter. I'm using regular male header pins for the alignment, and having tried it, I think 0.8mm is really too tight. Not sure how @andrew is using 0.7mm. Different pins I guess? Anyhow, next time I'll try 0.9mm hole diameter.
maybe my pins also have different factors, but indeed, the given holes are pretty tight. this helps to prevent unnecessary pcb movements, which is very important if you work with 6mil traces/isolation, as a small unwanted movement could result in wasted pcb. if you work with bigger traces/clearings then it is not as important.
I would recommend to stick to one size which is good for your selected pins and which does not let the pcb to move.
@neverdie said in CNC PCB milling:
How do I mill a slot? Do I treat it the same as a regular hole, except use a routing bit rather than a drill bit when it comes time to cut the slot?
you can mill holes, which are bigger than your drill bits, you can find a milling section in flat cam when you are working with the drill file.
you can mill slots as well, for this the slot has to be designed properly in the PCB designer software. you have to draw closed shapes on e.g. the edge cuts layer, then basically you have to follow the same approach in flatcam that is used to create the edge milling cnc job, but instead of the edge lines, you have to select the slots.
if you design it that way, then you can do both the slot and edge milling at once.
@neverdie the order of the process should be the following:
as I see your results, you could use alignment holes closer to your actual design's border, but it should be definitely out of the pcb's edge + milling tool width area.
the very thin traces are most probably caused by:
@neverdie as I see from the picture, you can decrease the cutting depth. this could help you to soften the force against the carving bits and it could also help you to use faster feed rates without risking a missing step or bit damage.
btw, what are your currently used parameters?
also, for the best results please be sure, that when you set up the tool width in flatcam, then it is originated from the previously mentioned formula, which uses the carving bit properties (end with + angle) and the cutting depth.
@neverdie I told you since the very beginning to make the firmware upgrade! 
@neverdie sorry, I'm abroad, with very limited availability, so cannot answer too quickly.
based on the mentioned facts it seems to me, that the X axis direction pin is sticked to one position, maybe it has a solder bridge to another pin, or vcc / gnd directly.
@neverdie don't stick to you missing dragon programmer. use an arduino as an isp programmer instead. also, if you burn the bootloader, next time you can use the usb connector for update.
@neverdie interesting.
the LEDs are driven by the communication line itself, so if you send a character on serial to the board, then basically your data will flash the MCU's RX LED, not the MCU.
there should be no problem at all with the touch probe solution/circuit. it equals to a simple button sensing on a common arduino's pin, it cannot cause the MCU's death, if you are connecting everything properly.
@neverdie I hope that you made the prototyping with the cnc
@boots33 I'm looking for some expect data type declaration / enforcement for the given value types. e.g. due to a mistake in my code, nothing prevented me to send 2 bytes uint16_t payload for the V_PERCENTAGE. so, the msg setters basically do not care about the msg type vs payload type/length validation, which could cause inconsistency or improperly used communication.
this causes my problem at the receiver side as well, because data type is not enforced for the given msg/value type.
this is how I see it now, maybe there are proper solutions for this.
by browsing the API documentation I did not find mapping details between the message type enums and their corresponding data representing format.
so, from where should I know that e.g. V_PERCENTAGE messages needs uint8_t and not anything else? as I see it is possible to send any data format for any message type.
if I have to handle the messages between my nodes then it is not that problematic, but if it has to be forwarded to the controller then it would be nice to have it standardized.
@boots33 thanks for the hints, I already implemented some PoC code which works perfectly!
@yveaux said in What did you build today (Pictures) ?:
@andrew Nice work man!
Where did you source the gray enclosure from?
thanks! the cover is also part of the original livolo (well, in fact a chinese clone of livolo) touch switch.
@boots33 is it possible to send S_DIMMER messages from one node (my switch) to another (actuator) without involving the controller and/or the gateway?
@neverdie said in CNC PCB milling:
With single sided PCB, I soldered the ground wire (for probing) to the copper cladding, just as the Chilipeppr author did. How are you handling it for two sided? If I do it that way for two sided, the solder bump may prevent the board laying flat on the wasteboard.
I use some flat metal weight connected to the given wire, placed on top of the pcb.
hackaday just released a relevant post:
https://hackaday.com/2018/01/04/guide-why-etch-when-you-can-mill/
@neverdie yes, I use male pins, with 0.7mm drill (so it is tight for the pin), 5mm depth. but this is really up to you, choose anything which you have easy access to.
@andrew said in What did you build today (Pictures) ?:
so, it is ready. I mean ready to SW development both the schematic and pcb design is now confirmed and fortunately theory meets the practice
it is assembled, programmed, tested, everything works as expected.
I did not mount it to the wall so far (I'll need a controller and real actuators first), but there was no issue with the communication between two nrf modules (both with PCB antenna) from cca 6 meter distance + 2 walls (10 cm brick) in between.
the touch panel's firmware will be enhanced as well as the controller's firmware, at the moment the touch sensing is reliable and a PoC code run on both of them for testing/debugging purposes. for the controller board I'm collecting additional information for the development on the following link:
https://forum.mysensors.org/topic/8831/which-sensor-and-msg-type-for-switch-dimmer-node-sender-only
hello everyone,
I'm currently working on a customized livolo touch switch (see https://forum.mysensors.org/topic/7836/what-did-you-build-today-pictures/162, https://forum.mysensors.org/topic/7836/what-did-you-build-today-pictures/163, https://forum.mysensors.org/topic/7836/what-did-you-build-today-pictures/292), which act as a "wireless remote" only. no direct power/lamp switching/dimming will be managed by this node, but the controlling only.
based on the instructions it provide (on/off/dimm level) the corresponding pair node has to do the necessary control.
the touch surface has two color LED feedback, so it should also receive messages from the controller to update its status when the light is switched from another location or from software.
I'm basically ready with the electronics, it is assembled, tested, everything works as expected.
so, my question is, which sensor node type and messages would be ideal for this node?
it would be also important to be able to communicate directly with the actuators without involving the controller, just to be sure, that lamps could be switched even in case of a "service outage". I'm also looking for the relevant technical details for this.
JFYI, final details (including hw/sw design) will be shared on openhardware.io as well.
andrew
@neverdie said in CNC PCB milling:
@andrew said in CNC PCB milling:
did you manage to create double sided PCB jobs in the meantime based on my suggestion and on flatcam's documentation? it is not a hardcore process, let me know if you stuck at a given step.
Not sure what kind of pins to use for the alignment.
I missed this reply from you.
so, you have to define the alignment holes, typically outside of the actual pcb area, in the "frame".
you have to define two of them, the rest will be calculated automatically.
the steps are exactly the same as that you can see on http://flatcam.org/manual/procedures.html#side-pcb
see the pic below. note, that you don't have to write the coordinates to the input boxes manually, once you click on the design area the corresponding coordinates will be copied to the clipboard, so you can use ctrl-v to fill out the settings.
@neverdie said in CNC PCB milling:
@andrew said in CNC PCB milling:
could you please explain how did you find/measure this?
- Decided upon an origen. Used Chilipeppr to "run test probe" to find the zero z-height. Zeroed x,y,z at that location.
- Did an autolevel, at 1mm spacing, over a 20x10mm area.
- Following this, returned to x=0, y=0. Ran another test probe. Ideally it would have come back as z=0. Instead, it came back as z=-0.048.
So, if at that point I were to actually run g-code with a cutting depth of z=-0.05, it would barely scratch the surface. Somehow during the 1mm autolevel probing, z became uncalibrated. If I were to re-zero z based on the second test probe, it would cut, but the cutting depth wouldn't be uniform.
Anyhow, my new rule is that if I come across a situation like the above, I throw out the auto-leveling and start over rather than executing the g-code. Often, the next autoleveling will have less discrepancy by step 3.
if your probe speed is too fast, then it could push the pcb at the given points and also it could damage your tip's end, as it was mentioned by @rmtucker, which could cause this issue as well.
@neverdie could you please explain how did you find/measure this? also please let me know the details of the executed job, including the G code generation properties/settings (e.g. feed rate, depth, multiple passes etc.) used in flatcam.
@neverdie I still use my default settings (see below). I re-applied these settings after I flashed the board to grbl 1.1f.
to be honest, after I found the right parameters for the PCB milling jobs I did not went further to fine tune the CNC settings, due to the lack of time. maybe later of the year, but currently I'm more than happy with the results.
$0=10 (step pulse, usec)
$1=25 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=5 (dir port invert mask:00000101)
$4=0 (step enable invert, bool)
$5=0 (limit pins invert, bool)
$6=0 (probe pin invert, bool)
$10=3 (status report mask:00000011)
$11=0.010 (junction deviation, mm)
$12=0.002 (arc tolerance, mm)
$13=0 (report inches, bool)
$20=0 (soft limits, bool)
$21=0 (hard limits, bool)
$22=0 (homing cycle, bool)
$23=0 (homing dir invert mask:00000000)
$24=25.000 (homing feed, mm/min)
$25=500.000 (homing seek, mm/min)
$26=250 (homing debounce, msec)
$27=1.000 (homing pull-off, mm)
$100=800.000 (x, step/mm)
$101=800.000 (y, step/mm)
$102=800.000 (z, step/mm)
$110=800.000 (x max rate, mm/min)
$111=800.000 (y max rate, mm/min)
$112=500.000 (z max rate, mm/min)
$120=10.000 (x accel, mm/sec^2)
$121=10.000 (y accel, mm/sec^2)
$122=10.000 (z accel, mm/sec^2)
$130=200.000 (x max travel, mm)
$131=200.000 (y max travel, mm)
$132=200.000 (z max travel, mm)```@neverdie said in CNC PCB milling:
How many microsteps are being used, anyway? I'm not sure where that's defined. Apparently these drivers support up 1/16 steps, but it might be that fewer are actually being used (?). If so, then maybe going to smaller steps would help?
I notice one of the Pololu boards has the potential for doing 1/32 steps: https://www.pololu.com/product/2133
and might even be drop-in compatible.
this cnc controller board is directly pulls the drivers' MS1,2,3 pins to high, which means that it is "hardcoded" to 1/16 microstep. you really don't need smoother steps than this.
@neverdie no. you don't have to remove the drivers. you have to measure everything in place.
in the mentioned pololu doc/demonstration it is also noted that the given Vref could be measured on the top of the potentiometer (video 3:15)
@neverdie said in CNC PCB milling:
@andrew said in CNC PCB milling:
did you checked the pololu driver configuration from the linked documentation?
See post immediately above yours.
ok, I thought that you already did it, I told it to you long time ago
my controller has 0.1ohm Rcs. the steppers are rated to 1.3A, I configured the drivers to 0.9V which limits the stepper's current to 1.125A.
@neverdie said in CNC PCB milling:
@andrew Are you planning to provide more detail about how to setup and do double sided PCBs, or is it pretty much RTFM at this point? Just wondering. Your earlier posts were very thorough and helped a lot.
did you manage to create double sided PCB jobs in the meantime based on my suggestion and on flatcam's documentation? it is not a hardcore process, let me know if you stuck at a given step.
regarding to the mentioned upgrades. I agree with @executivul, it doesn't worth to do that with this machine. feedback from steppers, elevation measuring etc are overkill.
it's capabilities are more than enough for very precise pcb milling, if you would like to do much more with it, then a different machine could be better instead. if you have issues with the results, then it is configuration / settings / cnc job issue. if you loose steps, then the given stepper driver is not properly adjusted (did you checked the pololu driver configuration from the linked documentation?) or your tool/spindle speed/cutting depth/feed rate is not good for the given job.
@neverdie why do you use any scaling factor at all? be sure you export the grbl files with proper metrics, then apply the given metrics settings in flatcam (it has global and project specific settings as well), then no scaling is necessary.
@rmtucker said in CNC PCB milling:
@andrew said in CNC PCB milling:
to make the isolation routing width larger, you should use multiple passes. this is necessary to create a large enough isolation width. to be sure that all copper will be removed between the different passes (e.g. due to cnc inaccuracy or backlash) you should use overlapping. see http://flatcam.org/manual/procedures.html#wide-isolation-routing
Just to clarify that what andrew is talking about is multiple radial passes with an offset further away from the track/pads each time.
Not multiple passes in the depth.
exactly
@neverdie said in CNC PCB milling:
Here's the Model 20 bit again, but this time with flatcam being told that its width is 0.25mm
how flatcam told you the width or how do you calculate the tool width? it should be specified by you, flatcam does not know how to calculate the tool width in case of carving bits, it varies with the milling depth and depends on the tip's angle and end width. please see the corresponding mathematic formula mentioned in my previous posts.
you have to generate the isolation routing G code for a specific tool/bit, it cannot be re-used for a different sized one.
@NeverDie oh, you've a lot of stuff and update since my last visit here. I've just a couple of minutes now, so I just quickly checked the new posts. let me give some further details/tips to you based on the issues I see:
happy hacking with the cnc
@neverdie said in CNC PCB milling:
I'm stuck. I converted my gerber to gcode using flatcam, and imported it into Chilipeppr:
On the one hand, it seems to have gotten the dimensioning right, as indicated by the Y1.48in and X1.43in. However, the grid that it's showing is out of sync with that. Each square on the grid is 5mm. It's as though Chilipeppr thinks the entire design fits easily inside a 5mm square, and so when I attempt to do the autoleveling, it comes out completely wrong.
you can mark the zero point in the pcb designer tool before you export the gergbel, or in flatcam, during the post processing. if you do not define it, then maybe the given zero point could have some "offset" to the effective design. it is not problem, but it could make your life easier if your zero is e.g. at the pcb's corner.
if you don't want to update the files, then in chilipeppr you can update the probe area to not start from 0,0 but from a given offset.
@neverdie you should use one depth, regardless of the trace width. for me 0.05mm worked, see my shared settings above. you should decide the isolation width, this is the main property for the given config, but you should stick for one milling depth only. if the requires isolation width is bigger than the tool width at a given depth, then it will use multiple rounds to reach the given width, but still, with one milling depth.
@neverdie for er11 fastening you should use two wrenches.
if you loose steps during the milling, then with the given feed rate / depth / spindle speed combination the cnc / spindle / steppers are not powerful enough.
if you wood milling depth is not constant then:
my availability for the next couple of days will be quite limited, so I wish you good luck for experiencing the router and for the first PCBs!
@neverdie I've a PS with the same parameters. it is enough.
@neverdie oh 
if you have a chance to power the cnc from a variable current power supply, then check the current it drains by starting from low to higher current. if it eats lot, maybe there is a short somewhere. you could also try to open the power supply and find a fuse.
good luck!
@neverdie said in CNC PCB milling:
The strange thing is that the Chilipeppr demo seems to mill at z=0.000. So, if I were to try to etch the pattern for real, I would have to "zero" z at an actual z value of, say, z=-0.5 or something (whatever depth I wanted it to etch at).
Is that normal?
Anyhow, I've been through multiple trial iterations with no bit installed and with the spindle disabled, and during all that the X and Y couplers have not come loose. So, I think that the Locktite has lived up to its name and solved the problem I was having earlier.
yes, the chilipeppr demo works like this. but keep in mind, that for "real" isolation milling, the milling depth which you used during the g code generation will be calculate from the relative z zero, so in that case you really have to set z0 to the pcb surface.
@yveaux thanks I finally managed to document it, there are some other stuff in the queue as well
@neverdie yep, I've a linux vm for flatcam and bcnc.
from my previous posts the PCB CNC milling came out as an interesting topic. maybe another method, working with photo resist PCBs and UV exposure, could be interesting for others. so, for those, who are interested in this, I just documented my solution (not the technique, but my tool) recently.
@mtiutiu just search for "cutting mat"
@neverdie said in What did you build today (Pictures) ?:
What is that spring loaded contraption? Is it for holding your PCB while you solder it? If so, I can see how that would be handy.
yes. I have a "third hand" station as well, which is good for through hole parts and pcb handling, but for smd, this could be a life saver.
this is the exact item which I ordered and which you can see on the photo:
https://www.aliexpress.com/item/8-12cm-Fixture-Motherboard-PCB-Holder-For-Mobile-Phone-Board-Repair-Tool/32767458535.html
one step further...
ISP works, FTDI works, test code works, and looks like a genuine board
now comes the hard part 
@neverdie said in CNC PCB milling:
@andrew said in CNC PCB milling:
you should use A5 connector
Does using A5 somehow automagically just work, or does it require additional software configuration?
it should work by default
@neverdie one more think I forgot to mention: after I assembled the cnc, I used a little wd40 across each axis and moved each from one end to another. it helped for smooth and "barrier-free" movements.
@andrew for first go for a single touch probing instead of a whole autoleveling session.
just for testing purposes, start the touch probing from a higher position and touch the gnd wire directly to the spindle's tool to see whether it stops or not. if not, you should stop it manually from the gui, otherwise it could break the tool.
if everything works well (so you proved that you connections to the pins and the belonging settings are ok), then you can run the simple touch probes or the autoleveling as well.
@neverdie said in What did you build today (Pictures) ?:
@boozz What are those 3 pin male connectors called?
I guess that is molex 3 pin tht pcb connector, like this https://uk.rs-online.com/web/p/pcb-headers/4838477/
@neverdie for the touch sensing you should use A5 connector from the headers, connecting it to the actual tool (bit), then a gnd (header's bottom row) connecting to the pcb's surface.
for the tool connection I use crocodile clamps.
screws: you did not fasten them enough. at the beginning I also missed some endpoints, but since I put the cnc together, I had no issue with any of my screws.
@neverdie said in CNC PCB milling:
@andrew said in CNC PCB milling:
with chilipeppr (in case of grbl 0.9j go for http://chilipeppr.com/grbl , for 1.1.f go for http://chilipeppr.com/jpadie) you can quickly run its default logo engraving path for testing / demo purposes.
Thanks! That provided exactly what I was looking for. I ran the demo with no etching bit installed, and at first both X and Y seemed to be working, but the adapter coupling eventually loosened on both of them to the point where there was no longer X and Y movement. I've re-tightened tem, and it's working again. I hope it lasts.
Not sure where I should go next from here though.
so, as this machine does not have limit switches installed, it is your responsibility to move the gantry to a position, from where you would like to start the job and which provides enough space for each direction movement. usually you have to set a relative zero at the given starting point.
what is next? did you adjusted the stepper drivers? if not, then do it (I shared the link above). this is necessary to be sure, that the steppers will be powered with enough current (so they will be powerful enough for the given speed related movement and to provide enough force) or will not be overdriven.
then, I would say try to engrave the chilipeppr logo to a soft material first, have some experience with the cnc.
then, as I mentioned, discover the flatcam tool and try to create an isolation routing job for a test pcb.
I already mentioned my confirmed settings for the given jobs (edge / hole milling, isolation routing).
you should sacrifice some boards for your experience
also, try to find your ideal g code sender tool by trying multiple ones.
@neverdie for the cable issue I ordered this cable organizer spiral, although not yet installed it
@neverdie the er-11 should be permanent. this spindle is not powerful enough to handle bigger tools and to mill harder materials.
you can start with grbl 0.9j, but it is worth to upgrade to 1.1f.
to the fw upgrade you can use a simple arduino as ISP programmer as well if you do not find your dragon.
with chilipeppr (in case of grbl 0.9j go for http://chilipeppr.com/grbl , for 1.1.f go for http://chilipeppr.com/jpadie) you can quickly run its default logo engraving path for testing / demo purposes.
@neverdie yes, it is for "isolating" the pcb from the frame.
@neverdie nice, so your wife saved the project :)))
be patient and do not power the spindle for couple of hours, while it is cold, as it could be wet inside which could cause shorts and other issues.
@neverdie unfortunately, as I mentioned, I don't have ER11 (yet), and I just read articles and vendor suggestions on the installation method, so I cannot provide experience based suggestions to that. as far as I remember nor concrete temperature was mentioned, so I would say you should not "overheat" it.
@rmtucker I did not measure the max rpm for the given spindle, but I use it on "max" (so spindle setting is 1000) for the given jobs.
@neverdie no, that is not normal, but this is most probably just a communication issue. which software is used for the terminal connection? try to change the cr/lf settings, or the flow control options.
@rmtucker it is not 1000rpm, but the pwm control for the whole spindle speed range. see the details in the official document.
once you use the spindle speed with the value of $30 or above, then the controller will drive the spindle with continuous voltage, without pwm, so it will use its maximum rpm.
compared to bigger cncs with bigger spindles (e.g. what you can see from @executivul's video above) , 2418's is not that fast (in rpm), on the other hand it should not be "very slow". can you show a video on that?
@NeverDie
firmware settings: it is stored in the EEPROM, but nothing guarantees that the same location will be used for the same parameters in case of different versions, so the output of "$$" command should be saved, this contains everything which you can manually set up if necessary.
ER11: take extra care during the installation process to not "harm" the motor's axis. usually the ER11 is pretty tight and howtos mention that the motor should be cooled (by the freezer) and the ER11 should be warmed up before putting them together, to help the mounting process and to prevent unwanted distortion.
I put the CNC 2418 assembly guide to my share, for ones it is interesting.
@neverdie once the assembly is done, you should adjust the stepper drivers' current limiting as well.
it is pololu a4988, you can find the corresponding details here:
https://www.pololu.com/product/1182
then, it is always good idea to have the basic settings exported from the board, just in case... you can do it by "$$" command sent from the g code sender gui or directly from the serial terminal.
currently I use the following settings, the machine might be able to create nice results with higher feed rates, but I did not have enough time to test it and I sticked to the current working config.
isolation routing with 2001 bits:
you can calculate the V carving bit's tool width for the given milling depth with the following formula:
tan(bit angle/2) * milling depth * 2 + bit's end width
for excel formula the bit angle should be provided in radians, so it should look like this
tan(radians(bit angle/2)) * milling depth * 2 + bit's end width
edge cut or hole milling with the 0.8mm endmill:
drilling:
the spindle should be 1000 everywhere.
most probably your board will not have a bootloader, so it will not be possible to update the firmware via usb serial connection (with avrdude), but it is worth to try it. for me it did not work, so I traced back the MCU pins to the pin rows and used ISP to upgrade the firmware to grbl v1.1f (the board will come with 0.9j if I remember correctly). do not forget to export the gerber settings before you upgrade the firmware, as it will loose those, and you have to re-assign the given values again, after the update.
the ISP pinout (from the pin row's top left corner):
Reset -> pin 2
SCK -> pin 3
MISO -> pin 12
MOSI -> pin 13
5v -> pin1
gnd-> bottom row(!) e.g. pin 1
JFYI: CNC 2418 assembly by me
CNC 2418 assembly timelapse – 05:41
— András Kabai
I'll try to make a blog to describe the whole pcb cnc milling, tools etc, as well as other diy projects. I'll let you know if there is any notable progress...
to drive/control these CNCs a simple Pi is powerful enough, but it is not necessary to use a separated computer for that.
chilipeppr runs in a browser (just open chilipeppr.com/grbl). it needs a "remote" serial service to connect over the network (on your local lan/wifi) as from the browser it cannot directly interface with usb. this remote serial service is just an additional software, which should run on a host what is connected to the CNC. this could be the same where you run the browser or really a "remote" host (e.g. a pi). chilipeppr also could stream webcam picture, so if you have one installed to the cnc then you can get realtime remote video as well.
it is nice, "modern", but online.
although bcnc isn't that nice as @executivul also mentioned, but I like it. it should run on that host which is connected to the CNC. I didn't have any issues with it so far, single touch z probing and autoleveling worked fine for me. this is what I use now.
both of them are cross platform tools.
as I work on os x and linux I did not tested windows tools. there are several more other options both for *nix like systems and for windows as well, but I don't have experience with them, so I cannot recommend anything else.
I don't use separated computer for the controlling sw, I use my laptop for this job. you can't leave the cnc alone for a long time, the whole process needs multiple manual activities, so from this perspective the "remote" controlling solution maybe not the best idea.
@NeverDie the autoleveling is the g code sender tool's responsibility, so from the mentioned toolsets chilipeppr or bcnc could do it. the given sw tool controls the cnc to probe the pcb's surface, measures when the given bit touches the pcb then makes a 3d map from the pcb roughness. later this 3d map is aligned to the g code which you get from other tools (from my mentioned example, it is exported from flatcam, which processes the gerber files exported from the pcb design software).
@ben999 this is the way how "bed compensation" could be done, and for precise isolation milling it is essential. for drilling it is enough if you just set an approximately zero on z axis, which could be also result of a manual setup or the g code sender tools also could handle the single touch probe.
this is the case when your mentioned touch probe could help, but without touch plate it is possible to do the probing the same way like in case of the autoleveling measurement but with one touch only.
@ben999 for pcb milling the z touch probe is not so useful. you should do autoleveling instead, on the whole target pcb surface.
for this the pcb surface and the tool itself should be connected to the cnc controller board dedicated pins (usually the tool is connected with a crocodile clips) during the mapping.
just quickly googled a video for that:
CNC 2418 bCNC pcb-gcode – 00:41
— TheVinylrider
@neverdie most of these entry level CNCs do not have limit switches. the controller board and the grbl firmware is able to to handle them, so you can install them anytime.
when you power up the CNC, then it will have a "zero" point at the given x/y/z position. then, you can move every axis to the right position and set relative zero (usually at the bottom corner of your PCB) through the controller GUI. every movement declared in the G code will be calculated and will happen from this point. at the end of the given job (e.g. one round of drilling, or one round of isolation routing) the spindle will move back to the relative zero point, and will give back the control to you.
here I elevate the spindle on the z axis and change the tool, then I zeroing out the z axis again with the new tool, load the next G code job and run it again.
if you have limit switches then you can declare a tool change position which will be used every time and the cnc can do homing to real physical zero point as well.
it is nice to have features, but you can do and handle everything without these.
@executivul regarding to the parallel port question, these days, for these tasks it is worth to have compatibility with the latest open source toolsets, so usb and grbl compatibility is a key point.
if you do professional cnc work, then you might need something different.
btw, it does not mean that parallel port version could not work, most of them could be easily "upgraded" to support the mentioned needs. e.g:
Build a ChiliPeppr Driven 3040 CNC – 24:26
— John Lauer
@executivul thank you for the tips and for the shared experience.
I agree, that the mentioned CNCs, have more robust structure, more powerful spindle, but I guess that the mentioned extra upgrade on the spindle is a bit overkill, especially just to create ad hoc proto PCBs at home.
just be clear, I know that higher rpm and more powerful spindle could produce better and faster result, ballscrews provide smother and more precise movement, I don't questioning that, but for the price/value/reason of the usage combo I think the cheap smaller versions also do their job quite acceptably.
2418 is not the fastest, not the strongest, but precise enough for this purpose and it is pretty cheap.
btw, once I'll have a dedicated working area for my hw hacking stuffs, I'll definitely buy a 6040 or 9060, it is long time ago on my wish list
in Hungary the VAT is pretty high (27%) which we have to pay on top of the customs fee. moreover, our customs and post response and processing time is very bad. the process could be speeded up if the shipping happens with e.g. dhl and they are allowed to do the customs, but then it also costs extra.
in the past year customs started to focus very much on packages coming from China, even cheaper and smaller products are captured by them and you are forced to pay them before you can get your stuff
so for me it was better to buy the cnc from EU, even if it was more expensive compared to the direct Chinese sellers, because at the end of the day, the overall cost was about the same (assuming that I would had to pay the customs and the VAT) but I received the package much more faster.
@scalz Well, in fact, at home I don’t make real but fake vias only, so basically I just use thin wires through the via’s hole and solder it on both side.
@sundberg84 I often use 0.4mm drill bits for vias without any issue. 0.3mm should work as well. The drill set I linked before contains the most frequently used drill bits for PCB drilling (0.3 – 1.2mm).
regarding to the traces, I have stable and reliable results with 6 mil (0.1524mm) traces / 6 mil clearance, which is also a limitation factor of several PCB manufacturer’s hobby/proto package.
@dbemowsk that is not a big deal. for first, if you get a promt like on the pic above, then it is a good indicator. then you can use "$" to get a text help. for the commands you should browse the grbl repo on github, which I already linked, it has a wiki as well.
@dbemowsk the serial console should provide a promt like this
@dbemowsk any serial console could do the job. I usually use command line tools on OS X or linux, such as minicom or screen, but you can find graphical tools pretty easy. if you are working on windows then e.g. PuTTY could be a good solution.
@dbemowsk said in CNC PCB milling:
@andrew I had made the assumption that it had to be somewhat precise being a lab instrument, but maybe i'm wrong.
well, that is just my assumption. with steppers you definitely could turn exactly as much as you have to, with normal motors it is much harder as there should be some feedback based control (e.g. the rotary encoders which you mentioned). moreover steppers "keep" their status in one fixed position until they receive another polarity change (so a step), while in case of standard motors it is not true and if the mechanical part does not prevent it, then their axis could turn unexpectedly based on the external force it receive.
@dbemowsk the serial interface to those controllers which are used by most of these DIY CNCs are simple serial over USB, which speak grbl.
if your motors are not steppers then I guess it would not be precise enough.
@yveaux they had items from China and from EU warehouse as well. with the search I mentioned you can find product like this or this
@yveaux search for "cnc 2418" with space separated, then you can find some one from Germany.
