Bill of materials

5 Articles

Improved Part Searches For JLCPCB Parts

October 11, 2020 by 29 Comments

Finding the JLCPCB component parts library frustrating to navigate, [Jan Mrázek] took matters into his own hands and made an open-source parametric search utility. We’ve all probably wasted time before trying to track down a particular flavor of a part, and this tool promises to make the process easier.  It downloads data from the JLCPCB parts site upon initialization and presents the user with typical selection filters for categories and parameter values. You can install it yourself on GitHub Pages, or [Jan] provides a link to his site.

For the curious, the details of how to pull parts information from the JLBPCB site can be found in the project’s source code.  We like it when a distributor provides this level of access to their part details and parameters, allowing others to sort and filter the parts in ways not originally envisioned by the site design team.  We think this is a win-win situation — distributors can’t sell parts that designers can’t find.

If [Jan]’s name sounds familiar, it should be.  We have written about several of his projects before, two of them are also PCB designer tools ( KiCad Board Renderings and KiCad Panelization ).

A New Method For Growing Watch Springs

November 2, 2019 by 26 Comments

Scientists at the Swiss Federal Laboratories for Materials Science and Technology (Empa) recently developed a new technique for growing watch springs to tiny specifications. As it turns out, the creation of watch springs is ripe with opportunity for new materials research.

The technique involves using photo-etching and electrochemical deposition into cold, aqueous solutions. Compared to drawing and winding Nivarox wires, this is a fairly unconventional method for manufacturing. For as long as watchmaking has been around, creating the balance springs has been one of the most difficult parts of the job. The wires must be drawn to a thickness in the hundredths of millimeters and wound and tempered to the exact hardness, ductility, and elasticity while compensating for environmental factors. Many substances change their properties during fabrication, so the Empa team decided to look to pure materials research as a way to find a means for fabricating balance springs that would remain stable.

They took silicon wafers (the same kind used for solar panels and computer chips), covered them in gold and a thin layer of light sensitive paint, and etched the shape of a spring into the wafer. The wafer was then dipped into a galvanic bath containing a salt solution from a metallic alloy — the spring acts as a cathode so that when an electric current passes through the bath, metal is deposited at the base of the spring. Once the spring is built up, it is dissolved from the mold and examined. After a bit of smoothing, the final spring is washed and sent to a lab for prototype production.

The electroplated springs are currently on display at the Laboratory for Mechanics of Materials and Nanostructures at the Empa campus in Thun, Switzerland. In the meantime, the first pilot tests are being wrapped up, and the team is beginning to work with Swiss watchmakers to see if their springs can hold up inside watch mechanisms.

[Thanks to Qes for the tip!]

Partsbox.io Wants To Organize Your Junk Box

November 18, 2016 by 45 Comments

There are many ways to divide the hacker community into groups. Tubes vs transistors. Emacs vs VI, microcontroller vs discrete component designers. However, one of the more fundamental divisions in the community is how you organize your parts. We’ve seen giant warehouses with carefully organized bins and cabinets full of components, and we’ve seen storage crates with tangles of wires and bits of electron-bending components scattered among the wires.

dbIf you are in the former camp, you’d probably enjoy partsbox.io (see image, right). If you are in the latter group, you probably need to check it out even more than the other people. The idea is simple: an online place to keep an inventory of your electronic parts. The implementation is not as simple, though. The web application will work on a mobile device or just about anywhere. You can view your components by type, by location (the shoe box under the bed vs the parts bin in the closet), or by a project’s bill of materials. You can use “known” parts or create private parts for things no one else has (for example, your custom PC boards, or those 3D printed brackets you made to hold a microswitch). If you add data for a component you can make it available to other users.

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StickerBOM For KiCad

February 9, 2016 by 28 Comments

When boards were larger and components mostly through hole, designers could put a lot of information on the silk legend – reference designator, values, additional text and so on. But with surface mount components becoming smaller and board real estate at a premium, modern boards do not have a lot of information marked on the silk layer. If you are building and distributing a short run of kits, perhaps for a round of beta testing, then [Adam Greig]’s StickerBOM python script for KiCad can be really handy. StickerBOM is a KiCad BOM exporter designed for people stuffing boards by hand. It generates a PDF for printable sticky labels, where each label reflects one BOM line from a supplier. You then stick these labels on the bags from your supplier, and they show you where the parts go.

The labels get printed with the reference designator, quantity, component value, package, vendor and part number. It also adds a drawing of the PCB with the relevant parts highlighted for easy location identification. To use it, schematic symbols must have the supplier field and part number added. The script can be run from the command line, or from the BOM manager in eeschema. The script is set up for Avery L7164 labels, but this setting can be changed. It’s still work in progress so there’s a couple of bugs to be aware of. It cannot process the bottom layer of the board, and the result is only as good as the data you provide. And if you have a large board with components spread all over, the resultant graphic printed on the label may not be ideal.

We are hoping this, and other scripts such as the Part generator and Cost spreadsheets or the script for mechanical CAD export, get added to future releases of KiCad. The KiCad version 5 Developer’s road map document already has some really nice feature additions in the works.

A Simple (and Dirty) Bill Of Materials And Stock Management Utility

January 9, 2014 by 36 Comments

As many readers may already know, when I’m not featuring your projects or working on the mooltipass I try to make simple things that may be useful to electronics enthusiasts. My latest creation is a simple bill of materials generation tool, which can also do simple stock management. Unfortunately for Linux users, this utility is made using Visual Basic functions in an Excel file.

It works fairly simply: just enter your schematics’ components references in the excel sheet, along with the corresponding Digikey webpage address. Click on the “fetch” button and the script will automatically get all your component characteristics from the internet and tell you the component costs depending on the number of prototypes you want to make. Then click the “sort BoM” button and your BoM will automatically be sorted by component type and value. Another functionality allows you to check that all the components present in your BoM are also present on the (very simple) Kicad generated one. Finally, using another Excel sheet containing your current stock, the Bill of Materials will let you know if you have enough components for the assembly stage. A video of the tool in action is embedded after the break, and you can download the BoM template here (.XLSM file) and the corresponding stock file there (.XLSM file).

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