Hello everybody,
I have a problem with the measurements inside kidcad 7.07 and once printed for testing.
I have created more than 20 pcb’s with the correct measurements checked with caliper to the millimetre.
These have to be exact to fit in the perfect place.
When I measure in kicad the measurements are correct according to the program. But when I make a printout to buy them, it is smaller than it should be.
The doubt is that I have to send to make these pcbs and apart from the expense if they are wrong, is that they take 15 days to arrive and I have to throw them away if they are not with the correct measurements. I have exported the gerbers but I have serious doubts that the measurements are correct.
It is impossible to modify without being able to measure correctly.
I can’t leave some sample screenshots of examples I’m testing.
My instinct here is that there is something not 1:1 between KiCad and your printer driver (or the driver and your printer). Does the same driver work with a different 1:1 output from inkscape or similar? Also, in KiCad, is the PDF from Print or Plot?
Also, 7.0.7 is quite old now. While I don’t know of any specific bug fixes related to printing, there may have been some. Consider upgrading to the current stable version 7.0.11.
I’m not going to try to read the ruler in the pictures you included, if there is critical info there please spell it out in the post. To include images directly, you likely need to use the forum a little more. See the FAQ for more details on that. New Member Information
Hi, thanks for responding so quickly.
The printer is new (HP 107w laser), it has 5 prints, its drivers and firewire are up to date.
Yes it is set to 1:1 on the printouts and kicad to.
I’ve tried printing a pdf and then print this one, but it’s not the exact measurement either.
I will take your advice and now update the kicad to version 7.11 and also try 8 (test).
I have a huge doubt that if there is something strange and the gerber also have this problem and nothing that I send to do, it will work.
Regarding the images, yes I have already read that when I use the forum a little more I will be able to post images (it was not a complaint, but a comment for the way I used to do it).
I will try what I said and keep you posted.
Any other ideas, you are welcome
I have never had a size mismatch between layout and gerber.
Pdf output is a different story. Many printers produce a slightly shorter image. And sometimes the pd driver has a fit to page option.
PC boards that are professionally manufactured using the manufacturing files (Gerber files, NC drill files, etc) that KiCad generates will be the same size as the board shown in KiCad.
The size of an image printed on a laser printer will not show the actual size of the PCB and cannot be relied on to confirm the actual size of the resultant PCB.
Laser printers will not print a true 1:1 scale without adjusting scaling factors (at least none that I am aware of) and even then factors such as temperature and humidity can distort the size and aspect ratio of the image (assuming its printed on standard bond paper) as the day progresses. Paper is not a stable medium if dimensional accuracy is important.
Hello,
Thank you both for your response.
I made the changes, upgrading to v7.11, re installed dirves, firewire and everything is still the same.
Yes, I understand what you are saying. But being an error of little more than 2mm, I started to doubt.
I see that you never had this problem, so I’m going to send it to print.
Hello, I have encountered the same issue with my project as well. I am using Linux Mint. I exported the PDF of my PCB to check its dimensions before sending it for fabrication, I was shocked to see that the PCB dimensions are not matching up with the dimensions i set in PCB Editor. I exported the PDF in 1:1 ratio and my printer is also set on 1:1 ratio. The exported PDF dimensions are off by 3mm, next I switched to Windows 10 and exported the PDF, here it is giving correct dimensions.
So my question is that is it some bug for Linux version of KiCad or printer driver issue?
You could start by removing that “urgent” in capitals from your title. We’re all volunteers here, donating our free time. Just that word alone made me skip this thread yesterday.
For the rest, also note that KiCad version numbers have two dots. and the three numbers have specific meanings.
The whole idea of checking dimensions with PDF and printers is bogus.
It’s very seldom, but I have to disagree with you. In my first years I often used a printout to check dimensions, placement and verify correct footprint placement. It was always useful. I have also used printouts (with inkjet as well as with laser printers) to produce homemade pcb. This always worked - there was no 2mm error on a A4-page.
And if @VaibhavK states that the printout is exact on Win10, but not on his Linux installation: this shows that’s not a distortion from the printer, but some issue in the area between kicad (if there are differences in the printing code between the OS versions), the used linux printer driver, the printer driver settings.
PCBs are manufactured to high precision. You can trust the process.
Yes, the pcb manufacturing process will work. But the printout is to check my work produced in the cad tool:
correctly defined footprints?
used the correct unit in the cas tool (imperial/metric), and also correctly converted given values between imperial - metric?
A printout is another check to verify my own work.
Admittedly I don’t use this method anymore - I have gained enough self-confidence in my work to skip this check.
It’s far easier to check things with an interactive program now. And there are checks far more easily done using features such as the net inspector. Just a couple of days ago I found that two power nets were shorted. A little mixup with power symbols, easily fixed. Another bug was a ground trace not highlighting. That was due to a broken wire in the schematic. With a printout you’d have to compare net annotations on the pads.
But the part I mean is bogus is expecting to find errors in the dimensions using a printout. It’s like trying to check the accuracy of an Internet disciplined clock with a battery operated bedside clock.
Long ago there were rumours that colour printers were intentionally not close to 100% accurate as a barrier to counterfeiting.
And then there all those PCs and printers out there defaulting to Letter rather than A4
Hello paulvdh
I apologize if I offended you with something I wrote or the way I expressed myself.
I understand what you are saying, again if you felt something was not correct, just comment it. Far be it from me to want my words to upset anyone.
I am very new to this, I am not young either, I am past 50 and some things are not so simple for me to understand. I have started a project without having much idea, but remembering what my grandfather taught me as a child in electronics. This is my first use of a program of this type.
Simply, not knowing the traffic in this forum, these were my words of help. But they are just words, no more than that and in a language that I don’t master so well.