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Feature By Andrew Woodfield Making simple & good-loºking boxes If you are anything like me, you make all sorts of electronic stuff. When I show off my latest creation, an attractive-looking device with a few pretty lights always gets a more positive response than my rough, lashed-up designs on unetched PCBs. T he final step of creating a new electronic device typically involves finding a box to suit it as it’s nearing completion. It’s a Goldilocks moment, except that I usually find absolutely nothing is quite the right size. I might buy something, only to change the design and then discover that it no longer fits in that expensive box! Frequently, I just need a simple box. One well-known approach is to lasercut something from thin birch ply (see Photo 1 above). You can also use this approach with acrylic sheets. Designing and fabricating these boxes is easy, particularly with help from the many free online design tools. These types of boxes are instantly recognisable; it’s the dark and light crenulated edges that are the giveaway. Frankly, that appearance is sometimes seen as less than ‘professional’, even if the electronics within are a marvel of design. An alternative is 3D printing. This approach is great in many cases, especially for unusually shaped prototypes. However, 3D prints can take an appreciable amount of time to design, and often even more time to print. I recently needed to make several boxes, the first for a version of an HF receiver, and the second for a small, short-range, low-power SSB transmitter. In both cases, I was looking for a quick solution while also delivering an attractive appearance. The receiver I was testing was built by Charles Kosina (April 2026 issue; siliconchip.au/Article/20079). The electronics are all mounted on a PCBtype front panel. It is designed to allow the receiver to be mounted in an offthe-shelf plastic box. However, try as I might, I couldn’t find that box or a suitable equivalent locally. Faced with this problem, and wanting to get the receiver into a box quickly to allow testing, I looked for other options. Solution one The first solution I came up with, Fig.1: the cross-section of the 3D-printed rails used in the first of these simple enclosures. 66 Silicon Chip Australia's electronics magazine shown in Photo 2, was surprisingly simple. In this approach, four corner rails are 3D-printed in lengths (and colours) of your choice. For this first enclosure, I made my rails 50mm long. In hindsight, they were probably about 10mm too short, and things got a bit tight inside. I slotted in a set of small rectangular ply panels cut from 2mm basswood ply sheets. That shape, along with the selected material, permits very fast and easy cutting. Being simple rectangles, they can be cut by hand with a metal ruler and a sharp craft knife or, as I did, with a laser cutter. One feature of this type of enclosure is that the burnt laser-cut edges are completely hidden. While the ply thickness was quoted as 2mm according to the label, the material actually measured 1.6mm, so that was the thickness I used in the corner rail design. I double-­checked this again on several other sheets from another retailer, and I found the same result. A third retailer, however, had 2mm sheets that were 2.1mm thick. Clearly, some variation exists in the industry. The cross-section of these rails along with a 3D view is shown in Fig.1. The holes were dimensioned to suit M3 hardware. With the 6.5mm thickness from the rails on each panel edge plus 0.5mm for the materials, a total allowance of 14mm is used when designing the panels. However, the back panel of the case requires no such allowance, and thus siliconchip.com.au ▶ Photo 2 (left): Charles Kosina’s HF receiver needed an alternative enclosure solution prior to bench testing when the specified enclosure could not be located locally. Photo 1 (lead): while easy to design and make, the appearance of many lasercut boxes does not reflect the excellence of the electronics inside. has identical dimensions to that of the front panel. The HF receiver’s front panel measured 160 × 65mm. I cut the following panels directly from the “2mm” ply using a laser cutter: ∎ Top & bottom panels: 2 <at> 146 × 50mm ∎ Left & right panels: 2 <at> 51 × 50mm ∎ Back panel: 1 <at> 160 × 65mm I used PC-based drawing software to create the outline of the back panel. This allowed me to precisely dimension and locate the holes for the DC power supply and the RCA phono-type antenna connector that I used with the receiver. The next version will add a 3.5mm speaker connector and an accessory connector for the optional colour LCD screen. I used CorelDraw to design this panel and to convert it to a suitable format for my laser cutter. However, there are many possible design packages, including free ones (eg, Inkscape). At a pinch, the drawing functions in standard office productivity software could also be used. During assembly, I gently sanded the edges of the panels that were inserted into the corner rails. While the drawing (Fig.1) shows sharp right-angle corners in the base of the slots, when 3D printed, there was a very slight rounding on the corners at the bottom of the slots. Sanding the edges with 180-grit sandpaper very lightly allowed the panels to fit precisely into place. I initially planned to use 6mm-long self-tapping cheesehead screws to hold everything in place. However, siliconchip.com.au Photo 3 (above): a smaller enclosure with curved edges. my elderly 3D printer ended up producing slightly undersized holes in the rails. I found some M3 hex bolts in my parts bin instead and tapped the holes in the rails to match. Incidentally, I designed and 3D-printed all the front panel knobs. This provided a neat overall appearance but, more importantly, it allowed me to use a set of knobs that fitted nicely into the available panel space. A second option I then designed a second smaller enclosure for a very small low-power SSB transmitter, this time an enclosure using rails with curved edges. The box, shown in Photo 3, measured 120 × 25 × 55mm. The small transmitter PCB and a 9V battery fit inside this little box. The new rails I designed for this enclosure were slightly smaller and subsequently faster to print (see Fig.2). The panels were equally fast to cut, again from 2mm ply, and the assembly was completed in just a few minutes. This time, I used 10mm-long self-­ tapping screws. While smaller overall, a total allowance of 10mm is used with the panels and these rails. For this enclosure with its 120 × 25mm front and back panels, the dimensions of the remaining ply panels were: ∎ Top & bottom panels: 2 <at> 110 × 55mm ∎ Left & right panels: 2 <at> 15 × 55mm Available files The industry standard STL files for the two rail styles described here are available for download from the Silicon Chip website at siliconchip.au/ Shop/6/3577 These can be lengthened or shortened using settings in most 3D ‘slicers’. These slicers drive the 3D printer based on the content of the STL files. Just prior to printing the file, the user can adjust several features of the final output, including scaling each axis. Fig.2: the rail cross-section used in Photo 3. Australia's electronics magazine July 2026  67 Ideal Bridge Rectifiers Choose from six Ideal Diode Bridge Rectifier kits to build: siliconchip. com.au/Shop/?article=16043 28mm spade (SC6850, $30) Compatible with KBPC3504 10A continuous (20A peak), 72V Connectors: 6.3mm spade lugs, 18mm tall IC1 package: MSOP-12 (SMD) Mosfets: TK6R9P08QM,RQ (DPAK) 21mm square pin (SC6851, $30) Compatible with PB1004 10A continuous (20A peak), 72V Connectors: solder pins on a 14mm grid (can be bent to a 13mm grid) IC1 package: MSOP-12 Mosfets: TK6R9P08QM,RQ 5mm pitch SIL (SC6852, $30) Compatible with KBL604 10A continuous (20A peak), 72V Connectors: solder pins at 5mm pitch IC1 package: MSOP-12 Mosfets: TK6R9P08QM,RQ mini SOT-23 (SC6853, $25) Width of W02/W04 2A continuous, 40V Connectors: solder pins 5mm apart at either end IC1 package: MSOP-12 Mosfets: SI2318DS-GE3 (SOT-23) D2PAK standalone (SC6854, $35) 20A continuous, 72V Connectors: 5mm screw terminals at each end IC1 package: MSOP-12 Mosfets: IPB057N06NATMA1 (D2PAK) TO-220 standalone (SC6855, $45) 40A continuous, 72V Connectors: 6.3mm spade lugs, 18mm tall IC1 package: DIP-8 Mosfets: TK5R3E08QM,S1X (TO-220) See our article in the December 2023 issue for more details: siliconchip.au/Article/16043 68 Silicon Chip Alternative panel materials The files corresponding to Figs.1 & 2 can also be used with panels cut from 1mm-thick (18 gauge) aluminium sheets available from several electronics retailers. I’ve also included two additional STL rails files for use with 0.5mm-thick (24 gauge) aluminium panels. These are more commonly found at building supply retailers. The 0.5mm sheets can be cut with heavy-duty domestic scissors in situations where access to a metal guillotine is not available. The front and back panels in either of the examples here can also be replaced by aluminium panels without any changes to other parts of the enclosures. The panels may also be made from thick card in cases where designers are uncertain about the final size or placement of parts on the enclosure (and we’ve all been there!). This is also an option for those on a limited budget. By applying inkjet-printed paper labels covered with self-­ a dhesive transparent film to the front and rear panels, a fairly robust and quite professional finish can be achieved. If panels are made from PCB material, these are usually 1.5-1.6mm thick and therefore nicely match the first set of rails. Adhesives Once all the panels are slotted and screwed together, they will all stay locked in place without the need for any adhesive. During prototyping, when you may wish to leave some of the panels off, such as the top cover and back panel, it may be necessary to use a drop of hot glue here and there to keep everything in place. If the panel thickness varies significantly from the slot width, a little adhesive may be required to prevent the panels from vibrating, particularly if that panel is used for mounting a speaker. Different enclosure sizes The enclosure dimensions can be altered to suit individual requirements. Just keep in mind the allowance required for the rails when dimensioning the panels. Let’s use the curved rails to demonstrate this. As designed in the STL files, these are 55mm long. You may, for example, want an enclosure that measures 60 × 35 × 50mm, as shown in Fig.3. The rails can be printed at a Australia's electronics magazine Fig.3: an example of a differentlysized enclosure. Z-scale of 50/55 or 91% to produce rails with the same cross-section but lengths of 50mm. Remember that these rails add 5mm to the left, right, top and bottom edges of the ply panels. So, for this new enclosure with its 60 × 35mm front and back panels, the dimensions of the remaining panels would be: ∎ Top & bottom panels: 2 <at> 50 × 50mm ∎ Left & right panels: 2 <at> 25 × 50mm 3D printing & laser-cutting services 3D printer and laser cutting services are now available for those who do not own such equipment. The first place to check is local public libraries. Over the past decade, many have begun hosting technology services, and facilities often include this type of equipment. Some also provide classes, and many provide a maker service, offering printing and cutting for a very modest fee. In the case of our city libraries, the charges for 3D printing are usually based on the item’s weight in addition to a small setup fee, and availability of the finished item is often very prompt. Failing this, some companies also provide a fee-based printing and cutting service, although these are likely to be slightly more expensive. Final comments This simple, fast, and low-cost approach to making enclosures has allowed me to dramatically improve the final appearance of some of my designs. It delivers a modern professional finish and, importantly, avoids the often distracting appearance of dark and light laser-cut edges on these boxes. It’s also very easy to modify the basic components presented here to cater for a wide range of requirements. Armed with this approach, I feel this solution is certain to also find a use around your SC workshop, too. siliconchip.com.au