Board size calculation incorrect?

Recently I’ve submitted a few designs that are exactly (or just under) a multiple of a square inch, but the DRC bot reports them as being larger.

For example, one board is 1.6 x 0.6" (calculated in Eagle and verified on paper) but the bot says it is 2.1756 x 0.6069. Another board is 1.35x2.86", but the bot reported 1.4537x2.8247.

I know that a .1" isn’t much, but .5" is… and I don’t want to sqeeze the boards down any further thru trial and error.

I’m using EaglePCB, and have verified that there is nothing on any of the layers that is outside the boundary of the board.

Any suggestions?

Thanks in advance,

Brett

Send me the files. dcarne at this domain. I’ll see whats up.

Cheers,

–David Carne

I have the same issue, board is on order. Batch process said the board is: 5.3585x2.5625 and $35. Actual design dimensions are 3.2625 x 2.5625. I haven’t received the board yet, status has said panelized for about 8 days now.

Phil

I noticed the same thing on a board I just submitted. It’s 2350 x 1360 mils, but comes up substantially larger when I upload it to the DRC bot.

I’ll let the SparkFun guys elaborate, but I was told there’s a bug in the DRC bot dimension calculator.

The workaround in some cases is to make sure the board is positioned at the origin (in Eagle). Changing the orientation of the board also resulted in different size calculations, so you might need to try a few combinations.

Personally, for 2 of my boards, the calculations never dropped to the correct # of square inches. But I also had a tighter deadline than what BatchPCB could provide (especially with the Chinese holidays this week), so I ended up using Advanced Circuits (4pcb.com). They have a $500 credit for new customers, so my entire order was free!

I’ll be back to BatchPCB for small prototypes though… can’t beat the price and quality!

The bug is on our too-fix list. Most of the online frontend is going to get re-written to use the code that the back-end checker uses.

Cheers,

–David Carne