Are photoplots still used in PCB manufacture?

[Diver300]

At one time, to get PCBs made, first photoplots would be purchased, so that a film for each layer would have to be made. I've seen one of the cameras that could take the 36 x 24 inch photographs.

There was vectorplotting and mechanical step and repeat machines.

Laser plotters made those redundant, but the films were often still purchased separately, and sent to the PCB manufacturer.

It then became usual to send Gerber files to get PCBs made. Nowadays the .pcb files from most PCB design softwares are understood by the likes of JLCPCB.

What I wanted to know is whether the films are still used? I wondered if some sort of laser scanning is done directly onto photosensitive board, avoiding the need for films.

I'm only asking out of curiosity, as obtaining PCBs is a matter of sending CAD files + money to the manufacturer, and later receiving the boards.

PCB drilling information has gone the same way. In the past, I've had drill plots produced, then drill files. Once I even used paper tape for a drill file. I've posted floppy disks containing drill files along with the photoplots. For some time I would produce drill files along with the Gerber files and send them. Now the drilling of holes is something that just happens.

 

[Visitor]

No, "driving of holes is something that just happens" is not true. An Excellon drill file must be sent along with the Gerber files to get a board made.

 

[rjenkinsgb]

Films are still used; exposing the whole area in one go is the fastest process.
See the info on the JLCPCB site - Step 1:

PCB Fabrication Process in JLCPCB Factory - EasyEDA open source hardware lab

In EasyEDA open source hardware lab, open source square pools all kinds of electrical design engineerings together to realize resource sharing easily.

easyeda.com

 

[Diver300]

No, "driving of holes is something that just happens" is not true. An Excellon drill file must be sent along with the Gerber files to get a board made.

I agree. My point was that I don't even have to bother with creating Gerbers and an Excellon drill file. I just send the .pcb file nowadays.

 

[Visitor]

I generate and send Gerber & Excellon drill files – then any fab house can make the boards and I have more control over the finished product.

But it certainly is far cheaper and easier to order boards than ever before.

 

[Diver300]

I think that JLCPCB charge a bit more if I send Gerber and Excellon drill files.

Sometimes they have added clever features to the solder screen, by dividing up large holes so that the squeegee doesn't drop into them, and covering the holes that are within large pads with screen, so that solder paste isn't pushed though the holes. I think that is why they want the .pcb files. However they haven't been all that consistent about those features.

There is always some work involved in making a design ready for production. One mistake I made recently was a pin 1 dot that was too close to a track. The PCB manufacturers had to ask me whether it should be connected or not, and didn't want the correct answer which was that I didn't care. In future, I will just overlap a dot like that, or add a track to connect it.

 

[Nigel Goodwin]

I think that JLCPCB charge a bit more if I send Gerber and Excellon drill files.

Why would they?, it's what they do.

 

[Buk]

Why would they?, it's what they do.

Perhaps it messes with their automation, meaning that they need to inject the separate files in later in the process sequence.

 

[Pommie]

At the price they produce stuff, it has to be fully automated.

Mike.

 

[Visitor]

I think that JLCPCB charge a bit more if I send Gerber and Excellon drill files.

Nope. No extra charge for Gerbers. If anything, there would be an extra charge for sending board files as it's an extra step for them.

Perhaps you're confusing that with the fact that some vendor-provided software packages charge extra to provide Gerber files, holding you hostage to use their service.

 

[Visitor]

There is always some work involved in making a design ready for production. One mistake I made recently was a pin 1 dot that was too close to a track. The PCB manufacturers had to ask me whether it should be connected or not, and didn't want the correct answer which was that I didn't care. In future, I will just overlap a dot like that, or add a track to connect it.

Why was the dot in a copper layer instead of the silkscreen layer?

 

[Diver300]

Why was the dot in a copper layer instead of the silkscreen layer?

There was no silkscreen. I tend not to use them as most of the components are surface mount and there wouldn't be a lot of point.

Most of the components have a silkscreen when they are in the PCB design program, which allows me to have a layout diagram that show where the components go and their numbers, but if that were to actually become a silk screen layer, it would often end up on top of pads. The component numbers would almost always be hidden by the components.

I could have a separate layer for what should actually be made a silkscreen, but it's another place where the design would need tweaking for manufacture.

 

[Diver300]

Nope. No extra charge for Gerbers. If anything, there would be an extra charge for sending board files as it's an extra step for them.

Perhaps you're confusing that with the fact that some vendor-provided software packages charge extra to provide Gerber files, holding you hostage to use their service.

Interesting. I'll look into that next time. The software I use can output to Gerber at any time.