In my opinion, you are agonizing over something that is less important than the overall benefits of have a finished 3D-printed product. Rather than calling it "bumpiness" I would prefer to call it the "surface finish".

The surface that is in contact with the bed will take on the finish of the bed surface, to every exact detail. I know because when I first got my Reality Ender 3 printer, I failed to setup the Z-zero adjustment correctly. I ended up with a clover leaf pattern that is permanently scratched onto the surface of the bed (hot plate). Now every object coming off of my 3D-printer has this beautiful signature clover leaf pattern.

Vertical walls will have a striated finish. Top surfaces will have a smoother finish. In all cases, there is no need to improve on the finish.

Trying to surface the finish on a CNC machine will not work. The heat generated by the face-off tool will soften the plastic and the result will be a mess.

You can try sanding the surface but in my opinion it this totally unnecessary. The natural finish of the 3D-printed surface is actually very pleasing.

Here is an example of a 3D-printed enclosure. The case itself is an off-the-self extruded aluminum enclosure. The front bezel and side panels are 3D-printed with no extra finishing done on them.

View attachment 306018

That's beautiful. What printer did you use for that?

 

That's beautiful. What printer did you use for that?

Creality Ender 3 Pro that was purchased in January 2020 just before COVID-19. There was no better way to endure the pandemic lock-down than spending time learning how to create 3D CAD models and 3D-printing.

The price has dropped dramatically and I recently bought a new Creality Ender 3 V2 since we do use the machines a lot in our household. When you have print jobs that run for 16 hours or longer it is nice having a second machine for smaller jobs.

 

In my opinion, you are agonizing over something that is less important than the overall benefits of have a finished 3D-printed product. Rather than calling it "bumpiness" I would prefer to call it the "surface finish".

The surface that is in contact with the bed will take on the finish of the bed surface, to every exact detail. I know because when I first got my Reality Ender 3 printer, I failed to setup the Z-zero adjustment correctly. I ended up with a clover leaf pattern that is permanently scratched onto the surface of the bed (hot plate). Now every object coming off of my 3D-printer has this beautiful signature clover leaf pattern.

Vertical walls will have a striated finish. Top surfaces will have a smoother finish. In all cases, there is no need to improve on the finish.

Trying to surface the finish on a CNC machine will not work. The heat generated by the face-off tool will soften the plastic and the result will be a mess.

You can try sanding the surface but in my opinion it this totally unnecessary. The natural finish of the 3D-printed surface is actually very pleasing.

Here is an example of a 3D-printed enclosure. The case itself is an off-the-self extruded aluminum enclosure. The front bezel and side panels are 3D-printed with no extra finishing done on them. Any rainbow patterns or coloration that you may observe is a result of the moiré patterns coming from the resolution of the photograph, the web browser and the display screen on your computer.

View attachment 306018

Hello again,

Oh yes that's nice. Came out pretty good.

I was also wondering, is there any DIP pattern G code on the web you can download?
This would be probably mostly G0 and G1 instructions to move the x y and z axis, and it would form maybe a 16 pin DIP pattern. You could download it, then add some G codes to add it to your intended total board pattern, most likely using the code more than once with coordinates changed.
I did not see any on the web yet.

 

I don't do it like that.
I do a PCB layout and let the CAD software generate the gcode. There is no need to mess with the gcode.

 

I don't do it like that.
I do a PCB layout and let the CAD software generate the gcode. There is no need to mess with the gcode.

Hi,

Yes, that's cool too, but I was wondering if there was any on the web available. Just thinking about it at this point.

 

I don't do it like that.
I do a PCB layout and let the CAD software generate the gcode. There is no need to mess with the gcode.

Hello again,

I basically wanted to get accustomed to the G code as that is the lowest level I can work with right now and I just wanted to get a feel for how that works.

I had another small question though.
What if I wanted to make a surface map manually, is that possible?
In other words, for example, I would move the head manually to x,y positions with z being a constant (or with the 'jog' controls) to 1,1 then press a button, then to 2,1 then press another button, then to 2,1 and press, then to 2,2 and press. All the time the z axis would be just touching the surface.
In each case I may have to enter the coordinates or something, or have them already entered via the H map settings in the Candle software.
This would be in essence mapping just the four corners of the board to be worked, assuming that would be good enough for now.
Is that possible?
I ask because some surfaces will not be conductive. Yesterday I did a quick test just to become familiar with some concepts and I just used a piece of cardboard. It was just a simple etching of a Christmas tree. The cardboard is not conductive so the H map idea would not be able to sense anything on the surface, I don't think. This would also be the case with a piece of wood that is not perfectly flat or there is some slight runout with the machine.

I have a 'sensor' now, which is a metal disk that you can place on the surface and when the bit comes down it will touch the top and that will record the surface height (plus an offset) and that detects the height. However, to use the mapping function I would somehow have to move that around the board to get the sensor to detect all four corners (or maybe more than just four points).

Any ideas here?

Thanks.

 

I ask because some surfaces will not be conductive.

For that case I use a touch plate - just a small piece of PCB with a wire soldered to the copper. When contact is made you know the tool is 1.6mm (the thickness of the piece of PCB) above the actual surface.

 

I use a thin piece of conductive metal, e.g. copper or aluminum foil.
But why do it manually? Why not let Candle do it automatically for you?

 

For that case I use a touch plate - just a small piece of PCB with a wire soldered to the copper. When contact is made you know the tool is 1.6mm (the thickness of the piece of PCB) above the actual surface.

Hi,

Oh you mean you can assume that the PCB board is completely flat and uniform throughout?

 

I use a thin piece of conductive metal, e.g. copper or aluminum foil.
But why do it manually? Why not let Candle do it automatically for you?

Hi,

I did not want to do it manually really, I thought that was the only way. I can try a PCB board I guess.

I also see other types of sensors now that fit into the collet. They are much more expensive though. Ever try one of those?

 

I can also see that there are lateral alignments that may have to be nearly perfect.
I tried routing a small piece of pine earlier today by digging out the corner along the length of the piece. The inward depth varied because the pine piece was not perfectly parallel to the front of the Y bed plate. It was only off by maybe less than 1/64th of an inch, but you could still see the variation.
If this was not corrected for a PCB, all the parts could look slightly rotated.

I guess I am still learning the basics. However, I managed to write a G code set to drill a DIP pattern and it did not take long at all.
Since it would be nice to be able to repeat this for several DIP packages on the same board, it would have been nice to have a form of a macro available. However, as I have learned now, GRBL does not support macros. That's very surprising because a lot of machining is comprised of repeating the same patterns over and over again for the same piece.
When I tried using a macro I placed it at the end of the program as described on the web. What happened was it never got called until the very end of the program and then it only executed one time. That was not the place were it should have been executed either which was strange.
The only workaround I see right now is to create a program that will process the original G code and form a new file with each macro placed inline. The new file would then be loaded into Candle and run as usual.

I do find it pretty amazing how much control you have over the milling and drilling positions and all that. I could even see just using a drilling set of G codes (as I did with the DIP pattern) and then hand drawing the traces and etching with a chemical as I used to do long ago. The drilling was the hardest part because you had to get the holes placed very accurately, and if done by hand it took time and care not to break bits.
I might try a 0.05 inch SMD chip pad set next. That's usually the smallest pattern I ever did by hand anyway. Anything smaller I would use a surf board with the pattern already etched. Those are pretty handy little boards too.

I am also wondering how you keep dust and debris out of the lead screws long term. Just a little 8 pin DIP package left quite a bit of dust. The wood piece milling left even more wood dust. Right now I am using a small vacuum to clean up, but I can see small granules being left scattered around the table. Over time these can accumulate.
Maybe there is some routine maintenance schedule to follow.

 

I am also wondering how you keep dust and debris out of the lead screws long term.
Maybe there is some routine maintenance schedule to follow.

Typically, industrial machines have used a concertina type bellows sleeve that fits over the ball screw.

 

Typically, industrial machines have used a concertina type bellows sleeve that fits over the ball screw.

Hi there,

Ball screw? What is that, and where is that located?
I don't think mine has that though.
I'll look up concertina type bellows and see if I can make one perhaps.

Ok looked that up. Looks interesting and I have some fake leather to use if needed.
Not sure what a ball screw is though, but I guess the bellows would have to be positioned near the cutter so it could pick up the dust immediately.
Thanks for the ideas.

 

Big machines have a vacuum skirt around the cutting tool.
I just stand there with a vacuum nozzle as it cuts.

 

Big machines have a vacuum skirt around the cutting tool.
I just stand there with a vacuum nozzle as it cuts.

Hi,

Oh ok
I guess I could do that.

 

You can check out CNC 3018 Pro for your PCB etching purpose.

 

You can check out CNC 3018 Pro for your PCB etching purpose.

Hi,

Thank you, but I already bought a 3018 of a different make.
However, would you happen to know the measurements of the two x axis bar guides and the lead screw diameter for that machine?
I was thinking of using some parts from that for the one I purchased at some point but want to verify that the Z axis head has the same measurements as mine does.

 

Ball screw? What is that, and where is that located?

Used by the servo/stepper-motor to transport the axis.

 

Look up lead screw vs ball screw.

https://us.misumi-ec.com/blog/lead-screws-vs-ball-screws-differences-benefits-accuracy/

 

No offense MrAl but is there a reason why when some other member posts a term you don't know that you can't Google it for yourself? You will learn more by doing that.