Author Topic: Practical pros/con of laser VS milling of PCB's?  (Read 11946 times)

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Offline IconicPCB

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Re: Practical pros/con of laser VS milling of PCB's?
« Reply #25 on: September 30, 2015, 09:54:55 pm »
Mephitus,

Sadly all of original drawings were pencil and paper, nothing in electronic format.

On the other hand Controls are implemented in LinuxCNC. Originally I used BLDC drivers designed and made in Australia. Drivers had a step direction interface ( for all intents and purposes they looked like stepper motor interface).
Set up was driven almost open loop that is to say LinuxCNC had no feed back signals. The loop was closed inside the drivers themselves.

When one of the drivers failed I replaced it only to find the driver hardware had remained the same but the firmware was optimised for a particular application and no longer behaved as need ( in my application).

This gave m impetus to do further work on the controls. A the new set up is based on analog drivers with tacho velocity feedback while positional feedback is applied to LinuxCNC through a Mesa 5I20 FPGA card runing hostmot2 firmware ( alla stadard setup under LinuxCNC).

Bearings and screws are preloaded  NSK parts.  Alfred Jaeger 33mm body diameter spindle completes the picture.

Spindle sits inside a purpose designed floating head assembly which allows for localised deviations in laminate flatness .

The work platen is tooled up with soft tooling. Delrin bungs are screwed into aluminium platen. The bungs are then drilled by the machine to accommodate 1/8" tooling pins. The tooling pin arrangement matches Gerber processing set up so that both data and product panel can be flipped over and retain precision inherent in the machine resolution.

Delrin bungs will wear out eventually or move with temperature and time. They are unscrewed and replaced with new bungs.

The work surface of the aliminium platen was also machined by the spindle itself to ensure a uniform surface at a uniform distance to the spindle collet.

The tooling pins on the milling machine match tooling pins on a laser direct imaging set up.
Laser machine is used to directly expose liquid photo image-able solder mask and component overlay.
Same Gerber data processing is employed to generatesoldermask andlegend information for both top and bottom sidesand same control arrangement is implemented. However laser machine is driven by linear motors and can achieve 15000 mm /min operation at 3000 mm/s/s acceleration.
9000mm/s produces good results at higher speeds and or acceleration ringing is observabe.
Finished boards are electrically tested on a PROBOT flying probe tester and if needed prototype boards are assembled on a Mechatronika M10V pick and place machine.


 

Offline The Magic Rabbit

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Re: Practical pros/con of laser VS milling of PCB's?
« Reply #26 on: September 30, 2015, 11:16:51 pm »
I want one of those laser circuit flatbed systems now. Ooooooh if only it were hot-swappable with a 3D print head, I'd be in heaven!

Sent from my XT1039 using Tapatalk

 

Offline IconicPCB

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Re: Practical pros/con of laser VS milling of PCB's?
« Reply #27 on: October 01, 2015, 01:01:40 am »
It is.

All you need is the signal from the extruder to switch the diode laser driver on.

Get a sixty dollar laser housing.diode combo build a current driver to suit the laser diode .. and PTOINNNNGGG!
 


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