Eagle Library for Hammond 1551 Boxes
2012/11/25 Leave a comment
Browsing through the company’s products, you can find a whole range of small translucent plastic boxes that are really well suited for small electronic PCBs, and can give a good product-ish look to any hobby project.
In this post you’ll find some hints for designing PCBs for Hammond boxes, and an Eagle library with PCB outlines for some of them.
This library’s models are based on the suggested PCB layout, found in any model’s datasheet, together with the mechanical drawings.
Layouts include the board outline, mounting screw holes and no-route areas for screw heads.
Board outlines are designed in the “Dimension” layer, so make sure to use that one as “board outline” when generating gerber files. Additionally, board layout quotes are present in the “Measures” layer, so remember to hide that layer when routing.
To use the symbols, just add the correct box symbol to the schematic, as if it is a new IC.
This will make the PCB outline appear on the layout window. Here just remove the default rectangular PCB outline, and align the new symbol with the origin.
This is a list of the boxes contained in the library:
– 1551G: 50x35x20mm (normal and single hole)
– 1551H: 60x35x20mm (normal and single hole)
– 1551K: 80x40x20mm
– 1551R: 50x50x20mm
– 1591XXA: 100x51x22mm
If you need a layout for another box, just take another one as a model and modify it for the new measures… once the base layout is in place, it only takes a little time to fit for a new one.
When placing connectors on the board, you want to be very careful on the alignment. For certain connectors, like terminal blocks, the component outline has to be aligned with the external side of the box (that’s about 3mm from the PCB border), so that you may only place that connector on one side of the box. For other type of connectors, like USB ones, you may just place them so that it is aligned with the internal body of the box, so that you can use all four sides.
If possible, try to get the connectors and the box before producing the actual PCB, so that you can test connector dimensions with a 1:1 print of the PCB.
Also, keep into account that lateral walls of the box are not straight, but are lightly angled towards the outside.
You can download the hammond.lbr file from the link below:
Sometimes you don’t really need a commercial box for your PCB… I’ve seen many hobby projects using anything from mint boxes to other old electronic cases, so if this does not fit your needs, just use your fantasy (and post a comment ;-)!