Printing on transparencies for UV exposure?

[Lighty]

Hi All

I tried the whole toner transfer method for making PCBs but wasn't happy with the results so I tried the UV exposure method, and I was very impressed with the detail, it's way higher.

The problem is, when I've had the transparencies printed the print is not totally dark, the printing company says it's the best they can do, So I was wondering what is a good printer to use? I have a HP LaserJet 1000 but haven't tried it as I don't have HP compatible transparencies and don't want to buy 50 (minimum qty) at quite an expense to realise they no better.

So, does anyone use this printer or could advise a good base model (cheap) printer that works well.

Thanks

 

[Sceadwian]

Print the exposure twice on the same sheet, you'll get double the toner, though you'll have to accept the misalignment of the specific sheet through the printer, to avoid the pinhole effect this is a good thing though

Make sure you're using a true laser printer, not an ink based one. Even the best bubblejet/laserjet printers can't produce a thick enough layer to properly block the UV light. True laser printers deposit a thick layer that will block a lot of light, and a double layer will block much better.

 

[3v0]

Print the exposure twice on the same sheet, you'll get double the toner, though you'll have to accept the misalignment of the specific sheet through the printer, to avoid the pinhole effect this is a good thing though

I think that would be worse then toner transfer results.

3v0

 

[Boncuk]

Hi Lighty,

I've also used two prints mounted on top of each other. As long as the board size is smaller than 80X80mm it works reasonably alright. The larger the print the larger will be the misalignment - until it reaches a point you cannot get a good averaging result by compensating from the center. Additionally the contours of traces and pads get blurred due to stray light.

There are photopositive and -negative transparencies on the market. They use the laser print and are exposed using UV-light (the same way as exposing an UV-sensitive PCB). Making a contact copy that copy will be deep black (without pin size holes in the traces and pads) and transparent. The effect is similar to the green TRF when using toner transfer.

This film requires normal development and fixing. A finished copy can stand a lot of mechanical stress, even slight scratches without getting unusable.

Using additional DIY solder stop the result will be an almost industry quiality PCB.

The advantage of photo transfer is clear: You can use one film for multiple (uncountable) reproductions of PCBs.

Boncuk

 

[jbeng]

Even the best bubblejet/laserjet printers can't produce a thick enough layer to properly block the UV light.

A few years ago, while I was a teaching assistant at our local community college, I used an HP1220c inkjet to make transparency films for PCB's. The films were very opaque and the finished boards were beautiful. The only problem I had was that the films had to dry overnight before use, else the ink would smear.

Jeff

 

[k7elp60]

I have been using a Epson R200 inkjet printer for about 4 years to do transparancies.
I deleted the attachment as I made a mistake. I did the layout but I did not etch the board.
I have a lot of boards and the inkjet printer has been great.
Sorry for the mixup.

 

[DirtyLude]

^ Nice board.

 

[Boncuk]

^ Nice board.

What's nice about the board? The trace sharpness or the trace routing?

 

[DirtyLude]

What's nice about the board? The trace sharpness or the trace routing?

Sharpness is pretty nice, but it's all right angles, large traces, and hard to see finer detail, like how the text came out. Makes it hard to critically judge the etching technique. Quite frankly I was just happy someone posted an example pic of a board they made and it's definitely clean and workable.

Routing, no, not so much.

 

[3v0]

Agreed. I would like to seem more people post their work. If we chew them up for what they do not know that is not going to happen.

3v0