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N O I T N E ATT s t is y b b o H d n a s r e n ig Project Des n w o ir e h t e k a m w o can n f f o e n o , y t li a u q l a profession s n ig s d n a ls e b la , panels When a SILICON CHIP project is released as a kit by one of the major suppliers, almost invariably it includes a front panel to make the project look professional. But what happens when there is no kit – or when you want a panel for one of your own projects? And what do R&D labs do? I t has long been one of the stumbling blocks in building your own projects: how to make them look as good as they work! Hobbyists are not alone in this – professional designers – even here at SILICON CHIP – have had similar problems in making a prototype look “professional”. There have been various commercial systems available over the years: perhaps the best known was the self-adhesive aluminium “Scotchcal” (and later “Dynamark”) labels from 3M. However, these were withdrawn from sale some time ago. Back in February 1999 we told you how we did it for many of our projects: by laminating a laser print or inkjet print with self-adhesive plastic and glueing that to the case. While that method works and looks pretty good, it certainly isn’t as permanent or hard-wearing as a proper silk-screened or engraved panel. But as far as the projects we publish are 14  Silicon Chip concerned, that isn’t a major problem. We just need them to look good long enough to photograph them – it’s up to the kit suppliers to include “proper” panels. But there are many times when we build a project which we DO want to keep for a long time and use, just as our readers would be doing. What we usually do in that case is make the temporary (printed) panel and then when the kits are released, beg, borrow or buy one from the suppliers to replace ours. Then (as often happens) something caught our eyes: a press release from Perth-based Computronics Corporation (www.computronics.com.au) promoting their new “Quick-Mark” system of producing self-adhesive labels, signs and front panels. Front panels? What was that again? By Ross Tester Computronics is not new to us. Readers may recall a little over a year ago (March 2001 issue, to be precise) we described an easy way to produce your own PC boards using Compu-tronics’ “Kinsten” photo-resist board blanks and nothing more than a photo-copied or laser printed PC board pattern on ordinary bond paper. We’ve made countless PC boards over the past year or so using this method and have achieved exceptional results. It’s relatively simple to achieve very high resolution (for example, two or three point type in board markings, too small to read with the naked eye but which can be read with a magnifying glass). If the Quick-Mark system was anywhere near as good as the Kinsten system, the panel problem could be solved. So we asked Computronics’ Kevin Dare for a few samples and some inwww.siliconchip.com.au structions – and set about proving it one way or the other. You be the judge! The Quick-Mark system There are two (or three) parts to the Quick-Mark system. First is a range of exposure films which set the letter colouring of the panel. This film is available in a range of colours: black, dark blue, red, green, light blue, brown, white and grey/silver. Second is a range of base sheets, which set the background colour of the panel – most are a plastic but there are also aluminium base sheets. Again, these come in a range of colours: the plastic are white, yellow, silver, transparent, red, gold, orange, beige and blue. There are plain and gold aluminium and also premium white and aluminium sheets. These have a thick, premium 3M adhesive, particularly good for sticking panels to rough, non- smooth surfaces and low energy materials such as polypropylene and polyethylene. They are also significantly more expensive. Third (and not usually needed) are the over-laminating films, available in transparent, matt and Lexan. For reasons which we will go into shortly, if the emulsion side of the exposure film is towards the inside, the film itself obviates the need for an over-laminating film. You can mix’n’match the colours of the exposure films and base sheets to your heart’s content. If you want a dark blue label on a yellow background, simply choose the appropriate (dark blue) exposure film and (yellow) base sheets. Like PC boards, the Quick-Mark system depends on exposing the pre-sensitized exposure film to UV light through a suitable image. But that’s where the similarity ends. Where the PC board is then developed, dried and etched, the QuickMark system can take a couple of different routes. That’s because the exposure film produces, at the same time, positive and a negative images of the original artwork. Which you use depends on whether your artwork is a positive (ie, black lettering/images on a white or clear background) or a negative (clear/white images on a black background). Once exposed, the two parts are separated using a special “Peeling Board” and the required piece of film is then www.siliconchip.com.au Here’s a selection of the colours available in Quick-Mark. The “Roman Road” sign also gives a good idea of the resolution possible with a good (high contrast) original artwork with dense blacks and clear/translucent whites. secured to the base sheet (which has self-adhesive on both sides). We’ll look at the actual mechanics of this shortly. The top piece of film is higher gloss than the bottom – this may also influence which one you use. If necessary, a piece of over-laminating film is also secured at this time. Finally, the panel/label is cut to size and secured to the project. Emulsion-to-emulsion We’ve already looked at the difference between positives and negatives but before we get into the nitty-gritty of producing a label or two, a word on a long (hyphenated) word: “emulsion-to-emulsion”, and also on “wrong-reading” and “right-reading”. What emulsion-to-emulsion simply means is that the emulsion, or toner image on the film (or paper) being used for exposure is in direct contact with the UV-sensitive emulsion on the imaging film. Basically, what you are doing is avoiding any UV light scatter or “bending” which can occur when you pass the light through a sheet of film or paper after the image. Especially in paper but also in the types of film used for laser printing, the light path can be interrupted by fibres and even defects in the material. If the light passes through the material first, then the image, what you get is a more faithful reproduction of the image. You’ll also hear the expressions “emulsion up”, “emulsion down”, “right-reading” and “wrong reading”, probably used in conjunction with each other. “Emulsion down” for all intents and purposes means the same as “emulsion to emulsion”. “Emulsion up” means the emulsion is on the side of the film closest to you (ie, away from the material being exposed). “Right reading” means that as you look at the exposing film, you can read the words normally. “Wrong reading” means that the words are back-to-front or mirror image. (Hold a sheet of normal laser-printed paper up to the light, unprinted side towards you. Notice how everything is back-to-front? That’s wrong reading!) Negative acting A short time ago we said that QuickMark produced both a positive and a negative at the same time. And so it does. But Quick-Mark should be April 2002  15 SIX EASY STEPS TO A PRO-QUALITY L 1: The better quality your artwork, the better your final result. Blacks should be as dense as possible regarded as a negative-acting process in order to get the final emulsion of the label or panel on the right side, thus avoiding the use of an over-laminating film. Of course, if you WANT to use an over-laminating film anyway (perhaps to create a matt finish or to use the super-strong Lexan film), it doesn’t matter which way around you go. Normally, though, you would use a right-reading, emulsion-down negative artwork to produce a positive label. Producing your artwork The first step in producing a professional-quality label or panel (using any system) involves its design. With today’s computer software, this task has been made relatively simple but there are some traps for young players! (1) Avoid too many fonts. Most panels/labels look best with at most two fonts – and often one of those is a variation of the other (eg, bold and normal weight). (2) Also avoid fancy fonts. For some reason, many people go straight to “Old English” styles of typefaces, which have to be amongst the most difficult to read faces ever invented. You might think Helvetica is boring – but you can read it instantly. And that’s what a good panel is all about! (3) Faces with serifs (the little strokes at the top and bottom of letters), swashes (flowing artistic flourishes), etc, are best avoided on panels. 16  Silicon Chip 2: Expose the imaging film to UV light through your artwork film. Test strips can be used to determine time. 3: Use the peeling board to separate the positive and negative exposures. Either/both can be used, as required. (4) Large logos might give the manufacturer a warm and fuzzy feeling but do nothing for the end user. Keep logo sizes down! (5) Linework should be neither too bold nor too fine. Bold lines might detract from an otherwise great design; fine lines can be difficult to reproduce. (6) If you are making a one-off panel for your own use, consider what is going to be near the device. Reversed panels (ie, white lettering on a black background) have tended to be out of fashion in recent years (some notable manufacturers excepted!). But if most of your hifi gear, for example, is white on black, a new black-on-white device (or a different colour) could stick out like a sore thumb! (7) When you’ve come up with your design, print it out on a laser or inkjet printer and ask other people what they think of it. Don’t be hurt by criticism! (8) Above all, keep type straight and on the same horizontal and vertical lines where appropriate. Nothing looks worse than higgledy-piggledy type! made for the production of high resolution, dense PCB artworks directly from any Laser printer. It will also accept copier toner enabling usable artwork to be produced from pre-printed originals. We understand Computronics will be stocking this material soon but at the time of writing, it was not available in Australia. So for the moment, we’re stuck with using ordinary laser/photocopy paper. By the way, don’t even think about using overhead projector transparency film. Its blacks are usually anything but! (Hold a printed sheet up to the light and you’ll see what we mean). As we found with Kinsten PC boards, a good quality laser print or photocopy works fine – as long as you get the UV exposure right. But more on this shortly. What you are looking for in your print is very dense blacks (you should not see any variation in darkness when you hold the page up to the light) and no tone scatter or scumming in the whites. Many laser printers are fully automatic, not offering an exposure (or “darkness”) control. But if yours has, experiment until you get the best possible blacks without affecting the whites. Photocopiers almost always have an exposure control. The same rule applies if you are copying a PC board pattern from SILICON CHIP (or an overseas magazine, for that matter). Here’s a tip for photocopying: Printing your artwork The instructions for Quick-Mark refer to transparent or translucent film for the artwork – they don’t mention using bond paper. But then again, neither did the Kinsten PC board instructions – and we’re achieving great results with that and bond paper. They do mention a proprietary film called “LaserStar”, a translucent film www.siliconchip.com.au LABEL, SIGN OR PANEL 4: Stick the film to the self-adhesive base sheet using a wetting agent for slip. Squeegee out air bubbles. 5: Add extra lamination if required; allow to dry then guillotine (or cut) the sign/panel/label to size. 6: And it’s finished. Remove the cover from the adhesive on the back and secure in its final position. always place a piece of black paper against the other side of the leaf you are photocopying. This will tend to mask the print and illustrations on that page, allowing you to adjust the exposure for best possible results. Don’t know where to get a sheet of black paper in a hurry? Raise the lid of your photocopier and press the print button . . . Ideally, if a positive label is required, a right-reading, emulsion-side down negative artwork should be used. Quick-Mark should be considered as a negative-working system. However, as we said before, Quick-Mark produces simultaneous positive and negative film. The difficulty about producing a positive from a positive is that the emulsion in the final label ends up on the outside, requiring extra lamination. If you want to make a positive label from a positive artwork, it should be wrong-reading, emulsion down. A piece of imaging film of the required colour (ie, the lettering and markings on the panel) is cut slightly larger than the finished panel size. Remember that this film is UV sensitive so should not be exposed to room light (especially fluorescent) light for any longer than is necessary. Put it back in the lightproof container as soon as possible. It must never be exposed to sunlight (direct or reflected). The film is placed in a UV exposure box (or frame) with the shiny (emulsion) side towards the UV source with the artwork between the film and the source. Exposure There are a couple of minor wrinkles here. First of all, the exposure time needs to be determined and that can be affected by the age of the material and the type of paper you are printing on. The second thing to watch is something we have already talked about: type of original (negative or positive) and emulsion side/reading. These factors determine how the film will be exposed relative to your original. Masking The film is masked to aid later peeling. Once you have laid the artwork on top of the imaging film you should apply two masking strips along two joining sides. For masking strips you can use offcuts of the black imaging film. This means you have two joining sides and one corner that have not been exposed to UV light. The top layer is peeled from the unexposed corner. Having this unexposed corner makes the peeling process much easier. If you do not mask as above, lifting K&W HEATSINK EXTRUSION. SEE OUR WEBSITE FOR THE COMPLETE OFF THE SHELF RANGE. www.siliconchip.com.au April 2002  17 an initial corner and the peeling itself is much more difficult. By definition, if you are using a big negative artwork with plenty of black opaque areas along the edges then masking may not be necessary as the negative is doing the masking for you. But if using a positive, masking will be required. Exposure The film is then exposed to UV for the required time. We cut several small test strips and exposed these for various periods to determine our optimum exposure time – somewhere between 15 and 25 minutes or so for our setup. We were using the Kinsten UV exposure unit; if you are using another UV source, your exposure times may be different. Just experiment until you get an acceptable result. Exposure time is a compromise between ensuring sufficient UV light gets through the white paper to the sensitized film underneath but not enough to start “punching through” the black (toner) areas of the artwork. Exposure time using high contrast film is dramatically less: seconds, rather than minutes. Peeling the image An adhesive-coated “peeling board” is used to help separate the film once exposed. Lay the film onto the peeling board with its glossy side up (the side which was exposed to UV) and smooth out the film. Peeling is a bit tricky. First you need to separate the two layers of film with your finger nail at one corner, then grasp that raised section with your thumb and forefinger and peel it (away from the corner) without raising the film up. In other words, peel it back on itself – as you would do in trying to remove an adhesive bandage from your skin: do it quickly in one movement and it doesn’t hurt as much! It is also vital that this be done in one, smooth, continuous motion – if you stop or hesitate, the panel could be ruined by lines or imperfections. When the two pieces of film are separated, you’ll find the top piece is a reversed image of the original artwork with the coloured emulsion side underneath (in other words, if you used a negative, you’ll now have a positive, right reading, emulsion side down). 18  Silicon Chip The other piece of film, still stuck to the peeling board, will have an exact duplicate of the original artwork with the coloured emulsion on top. You can use either piece of film as your panel, depending on which way around you want it to look. Now you should start to understand why we made such a fuss of positives, negatives, emulsion sides, etc before; if you only had positive artwork and wanted a positive panel, a positive artwork, right reading emulsion side up is produced, (the same as an ordinary letter is produced). This is then turned over (wrong reading emulsion down) placed on a piece of imaging film and an exposure made. The image is then peeled and the bottom piece of film is used. On the peeling board this is wrong reading emulsion side up but when removed and turned over and stuck to a base sheet produces a right reading, protected emulsion panel. Laminating Now comes the easiest part: laminating the piece of film to the base sheet. The base sheet is not UV-sensitive so you don’t need to take such precautions with it. Cut a piece of base sheet just larger than your label and place both it and the label film, in a plastic tray (or perhaps on a large newspaper). Peel away the protective coating from the coloured (top) side of the base sheet and spray both it, and the label film, with a fine mist water spray into which you have added a couple of drops of concentrated household detergent. Don’t use enzyme-based detergent: it will damage the adhesive. The “slippery” water allows you to place the film on the base sheet without the “sudden death” of most contact adhesives. You should be able to slide the film around a little should that be necessary. Once you are happy with the position, “squeegee” the water out from under the label. Computronics have an applicator pad for the purpose which you might consider if you are doing regular labels – otherwise, squeegee it using a soft cloth. Some small milky blotches may appear between the layers of the label: don’t worry, these are quite normal and usually disappear after a day or so as the water dries out. Squeegeeing as much liquid out as possible tends to minimise this effect. Extra lamination If your image is on the upper side of the film and/or if you want to change the shiny label to matt or cover it with the tougher Lexan, you do this by using over-laminating film. Otherwise, you don’t need to do this because the emulsion will be “sandwiched” between the imaging film and the base sheet. Finally . . . Now’s the time to cut your panel to size (preferably with a guillotine, but scissors can be used) and fix it to the object required. The same type of acrylic adhesive is on both sides of the base sheet so again, a fine spray of slippery water (water/detergent mix as above) can give you a bit of movement. Acrylic adhesive normally takes some hours to finally cure but when it does, the panel will be very tightly stuck on, by gum! Cost The Quick-Mark components are not cheap. However, when alternative methods may be non-existent or much more expensive, it all becomes relative. The imaging film costs around $50 per sheet or about $35 per sheet in a pack of five. Each sheet measures 305 x 508mm, so you should get many projects out of a single sheet. Likewise, the base sheets are 305 x 508mm. The normal sheets cost about $30 each or about $21 each in a 5-pack. The “premium” sheets are about $44 each or $31 in a 5-pack. Large peeling boards are about $50, small about $38. They also have application fluid to help enable accurate positioning of the film on the base sheet. Personally, I would take their tip and substitute ordinary water with a couple of drops of concentrated washing-up liquid in a sprayer bottle (cost about two dollars compared to about $40!). Where do you get it? For additional information, refer to the Computronics website at www. computronics.com.au or call (08) 9470 SC 1177, fax (08) 9470 2844. www.siliconchip.com.au