I exported 300dpi image from eagle and pasted into a A4 300dpi blank image, but when i took the print out , the sizes of the ICs are not matching, what can be the problem ?
There could be a few problems. Did you make sure that when you exported the image that you exported it at a scale of 1:1? That might help.
Also, from my experience, when printing/exporting the PCB layout as an image, Eagle always seems to be a little off with the size. What I would recommend doing is to mess with the zoom/scale until the printout matches the actual dimensions. Then your ICs should match up perfectly.
Are you just trying to print/export an image of the board layout, correct? If so, you need to ensure that you are trying to print at a 1:1 scale. To do this make sure that box that says "Scale Factor" has a 1 in it; otherwise your layout image will be either bigger or smaller than it should be.
You may want to look at how you are "printing it" from the image. I exported an image of a PCB from Eagle at 300dpi and examined the resulting png file in a photo editor and the number of pixels is exactly correct.
creating bit map artworks is not a recomended way of doing things, again I go with printing 1:1 or if eagle has a bespoke post processing option for creating artworks use that.
As I said earlier, you need to look at how you are printing the image. Adobe pdf Reader usually selects "fit to page" by default - you need to turn that off.
I have printed that 1:1 from Adobe and the pitch of IC1 is 2.526mm - is that what you are measuring? That is probably paper shrinkage in my laser printer. Measuring the pdf (by eye, at 1000 pixles per inch) it seems to be 0.09989" pitch - close enough to 0.1". So, I think your pdf is OK. Your problem is printing.
varun ,
that is not the way you create a pdf from eagle. how do you use the artwork with components marked on that? Is it a screen for top layer?
EAGLE has inbuilt pdf creation possibility. while print ting , perhaps you select the layer needed as we dont need many other layers. then leave the printer selection second button allows you to save a pdf direct.
suppose the file is 'mybrd". now name the file as "mybrd sold" for solder layer and 'mybrd top" for top layer- incase two layer board. direct the file to be saved in the same foolder that holds the brd and sch files. it gives a clean correctly dimentioned artwork, once you select the print ratio as 1:1. you can print that pdf using adobe.
the printer sizing should be set to 'none' even the centring etc can be cancelled. I do many boards.like that and i get perfect diomentioning. Ofcourse i use 600dpi mode with my HP Laserjet P1007.