Planning designs around materials

Planning designs around materials

Posted Posted in FAQ, How to

Sometimes, customers need guidance about the best materials for their projects. If we consider how products will be used and where they will be displayed, there’s usually a good solution.

Material properties

Plywood that has laminated layers. Mdf is pressed into fibre boards of different thicknesses. Both become stronger with increasing thickness. Even at 3mm, plywood’s laminated layers give strength in two dimensions. It’s ideal for making small pieces like keyrings and golf bag tags that endure heavy usage, and it’s cost effective too.

Oak can snap with the line of the grain when there are imperfections in the grain called shakes. Other solid woods don’t have shakes.

Perspex is very robust, but it can shatter when dropped or snap at narrow points. Its broken edges are sharp edges and they cut skin easily. They’re so sharp I haven’t felt injuries at the time.

Mylar and polypropylene are bendy and flexible and can be almost indestructible. I use polypropylene for ballet tutu templates that need to take being snipped against with shears, but can bend with the netting. Rigid templates wouldn’t work.

Design delicacy

If a design is delicate, then robustness needs to be built into the design to ensure it will perform. As a rule, I find that keeping narrow areas of a design to 2 to 3mm wide works with any material in most cases. Here are my top tips for designing artwork for laser cutting.

treated oak sign mounted on stone gateway

Will the products be handled?

If objects are to be handled, especially by children, materials need to be chosen with care.

Wood is chunky and light. I’ve made giant plywood and mdf jigsaws with FifeX and The Malting House Design Studio that have worked really well.

Coloured perspex models (pictured at the top), coloured Valchromat and foam are good options too, and extra pieces can be made just in case.

Outdoor display

Which materials will stand up to the weather or survive being mounted in the ground?

Green oak and green larch are ideal for outdoor use without any treatment at all. They’ve been used for building for hundreds of years and can survive in the ground for 20 years or more. They make great wayfinding posts, signs and plaques.

Other softwoods and hardwoods need varnishing every year or so to protect them from the weather. If there#’s no budget for maintenance, it’s best to choose a low maintenance wood. Green larch is a cost effective option if green oak is too costly.

Marine ply is suitable for outdoor use with treatment. Unfortunately, laser grade ply is indoor grade and will only withstand outdoor display with very regular treatment.

Perspex, on the other hand, is perfect for outdoor use. It’s weather proof, is UV stable and doesn’t rot.

Mylar and polypropylene are perfect for flexible stencils as they can be washed.

 

Have you got a product you’d like to develop but aren’t sure how? Contact us or ask for a quote.

tools of my trade calipers

Tools of my trade – calipers

Posted Posted in FAQ, How to

Where would I be without my trusty calipers? They might be small, but I use them every day and they allow me to double check within seconds how thick a material is.

With laser cutting, the principle is to cut at maximum speed and the maximum power required for that speed for a clean cut through. Machine settings I select for 10mm perspex are different to the ones I’d choose for 1mm card.

If a material is a bit thicker than expected, even by a fraction of a millimetre, the chances of not getting a clean cut through increase. As a result, materials and production time are wasted.

Sometimes, production is successful, but if cut parts are designed to slot into each other and are too thick or thin, fit is not good. There’s a case study about this here.

Solid wood

It can be tricky to get sheets of solid wood cut to an exact thickness as they need to be cut with a saw and sanded down. They always need to be checked and I sometimes perform test cuts before starting a job. And as each piece of wood is unique with slightly different densities, tests are a wise precaution anyway.

Wood isn’t made in a standard process like perspex is. Tree type, where the wood came from in the tree, its growing conditions and how the wood was processed can all affect how the wood behaves.

measuring calipers

Perspex

Perspex is usually pretty reliable in thickness as it’s either cast in sheets of a certain thickness, or it’s extruded through rollers set to a specified thickness. Some brands need to be cut a little slower than others. There’s a blog about perspex here.

Birch plywood

When I buy birch plywood, the thickness described is nominal, not actual.

Nominal 3mm ply is usually 3.1 to 3.2mm, and 4mm is often 3.8 or 3.9mm. As it’s made of laminated layers, final thickness of a sheet depends on the thickness of its layers.

Some thicknesses of ply can look similar to others. I regularly use 3, 4, 5, 6 and 9mm. Sometimes, I’ve selected a piece of 4mm instead of 3mm, or 5mm instead of 6mm by mistake. Measure twice, cut once as a wise person once said!

If I pick a thicker piece by mistake, I don’t get a clean cut. If I select a piece that’s too thin, the work can burn on the back.

Cutting a material too slowly with too much a power damages final product quality. So checking before production makes sure products are right first time.

 

If you’ve got any questions about laser cutting and engraving, contact us and I’ll do my best to answer them.

Can I raster engrave using vector artwork

Can I raster engrave using vector artwork?

Posted Posted in How to, Prototyping

A customer asked me this last week as we discussed her new product ideas and how to add detail to cut out shapes.

The answer? Yes, you certainly can raster engrave using vector artwork, but there’s one major pitfall to avoid.

There are two ways to create vector lines with any thickness. One works really well in all situations and the other works in some scenarios, but not others. I’ll show you why.

The problem: how vector lines are seen by laser software

This is the biggest thing to get your head around. Vector lines can be created and then made to look a certain thickness, anything from hairline to 2.5mm.

If you view the artwork as a simple wireframe, you see what my laser cutting software sees – a hairline line, however thick you may have made it appear. To raster engrave to get the same effect, I have to follow these steps.

Step 1: To raster engrave the area, I’d select the artwork element

Step 2: Convert the selected lines into bitmaps while leaving other lines as vectors. This keeps the lines at the thickness shown on the screen so they doesn’t revert to hairline thickness at step 3. All the other lines for cutting and vector engraving need to be in that format.

Step 3: Export the artwork with the different elements to my software that tells the laser what to do with the artwork.

This can work for simple designs, but it can be a nightmare with more complex ones. Following my fool proof method below avoids all these problems.

Fool proof vector artwork for raster engraving

Kate decided that she wanted to add raster engraved details to her laser cut goose shapes. Raster engraving was the look she wanted.

I asked Kate to imagine a thick black line, say 40mm by 5mm. To have this line raster engraved, I told her she’d need to create a box 40 x 5mm using vector lines. I’d instruct the laser to raster engrave that rectangle.

If each element she wanted raster engraved was outlined by a surrounding line, the areas inside those lines could be raster engraved. This is how I’d treat the green feathers in the artwork above. Or if Kate wanted them vector engraved, the outline lines could be line engraved. It’s an easy and flexible method.

Kate Millbank vector engraved goose

Engraved geese

As it turned out, Kate wanted children to paint the geese. I suggested that the raster engraved feathers could be lost under the paint. It would be a shame to make a more expensive product with detail that could be lost. Vector engraving would be cheaper than raster engraving and would create outlines that the children could paint in.

This was a perfect solution for Kate. She’d given me foolproof vector artwork, so all I had to do was code the feathers for vector engraving. The results are shown in the picture above.

 

Have you got a product you’d like to develop but aren’t sure how? Contact us or ask for a quote.

 

Other artwork blogs that might be useful:

Designing artwork for laser cutting

Designing artwork for raster engraving

Cutting and engraving using the same artwork

Are vector and raster engraving different

Designing artwork for raster engraving

Designing artwork for raster engraving

Posted Posted in Artwork, How to

There are two ways to provide artwork for raster engraving, the fill in engraving shown on the board engraved for the Royal Botanic Garden Edinburgh above.

Pixel based files

Pixel based files include png, jpg and bmp files. They must be provided in black and white at a print quality resolution of 300dpi or greater to ensure good quality engraving.  Any pixellation in the image is seen in engravings!

Sometimes, customers provide artwork from the internet. While these look good on a computer screen, they aren’t good enough for engraving (or printing) as they’re only 72 or 96dpi.

And if pixel based images are rescaled, they can lose quality and become pixellated the more they’re processed through resizing. All these potential problems can be avoided by using vector files.

Vector files

Vector files  include ai, pdf, dxf, eps and svg files. They are made up of vector lines, not pixels as png, jpg and bmps are. Artwork for the engraved board at the top was created by pdfs and is shown below.

A huge advantage of vector files is that they can be rescaled to the size a customer wants without loss of image quality. Files are rarely provided at the scale required for a job, which means that resizing a logo or other artwork is inevitable.

Vector files also need to be black and white with no greyscale.

 

Why black and white?

Lasers can’t engrave in colour. The colour of engravings depends on the colour that the material becomes when it’s burned by the laser at the speed and power selected. In the case of wood, you can get deeper shades of brown and greater depths of engrave with increasing power or reduced engraving speed.

As the laser either engraves or doesn’t engrave, artwork needs to accommodate this. Generally, I recommend that the parts of a design to be engraved are black and non engraved areas white. Shades of grey can be achieved with different densities of black pixels like old fashioned news print, and the black pixels will be engraved to give a grey effect.

Why doesn’t greyscale work?

When the laser sees a shade of grey, it decides whether it’s dark enough to be black and engraves it as black, or decides it’s light enough to be white and doesn’t engrave it.

 

Have you still got unanswered questions? Email me at jane@laserflair.co.uk.

Follow these links for my top tips for designing artwork for laser cutting and laying out vector artwork for laser cutting .

commissioning a video

Commissioning a work video

Posted Posted in How to

This year, I decided to commission a video to show how I work. Since I started posting short videos of the machine at work on social media and my website this year, I’ve realised how much it helps customers understand what I do. And as video is increasingly important criteria for Google to prioritise websites in searches, I knew that I could kill two birds with one stone.

I had become more confident at filming the machine using my phone, but I knew that making such a video was beyond my abilities as I wanted something sleek and professional.

Finding a supplier

Kirsty Thomas of Tom Pigeon was one of my earliest customers. Her son Jude, who has just started a film studies course, made a video for her about designing and creating her prints. It was just the kind of format I wanted.

Jude agreed to work with me. Then we discussed what I wanted and what might look good. Then he came to the workshop during the summer to film me at work.

compressed air
compressed air guage

Filming

It took me some time to decide what process to film so we could organise a time for Jude to visit the workshop. In the end, I decided on my own plywood business cards. They’re my design with my logo, they’re quick to make and both cutting and engraving are involved. I wanted to show both processes.

Jude thought that the business cards would work well. He suggested keeping the video 30 seconds long so that viewers wouldn’t lose interest.

Jude was only in the workshop for an hour. He filmed me creating the artwork and colour coding it for cutting and engraving, and setting up the machine. Then he took lots of production shots as I cut a sheet of cards. Thankfully it was a bright day and shots taken inside the machine were well lit. Jude was worried that the window in the machine lid and its interior light might not illuminate the shots well enough. And he loved how the wisps of smoke generated during the process gave ambience to the cutting shots.

Post production

Once Jude thought he had enough footage, he went home to edit and add a soundtrack. He didn’t need to come back and retake any shots. Then he sent me a first version that I wanted some changes made to. Some parts of the process were shown in the wrong order, and we tried three different soundtracks, but it was perfect after two edits.

In the end, the finished film was 48 seconds long. As it showed lots of relevant process steps and was well within one minute, Jude though that it would work at that length.

I’m delighted with the finished piece. It’s on my scrolling website home page and YouTube channel, and I’ve shared it on Facebook, LinkedIn, Twitter and Instagram. My only regret? That I didn’t do it sooner!

how to lay out artwork

How to lay out artwork

Posted Posted in Artwork, How to

Some projects have very complicated artwork where many intricate pieces are laid out on one sheet of material. The artwork for Four by Two‘s Perspex model for Studio B was a good example of this, and one sheet is shown above. I’ve put together my top tips for laying out artwork like this for laser cutting and engraving in one handy blog. I hope you find it useful!

How much artwork should I put in one file?

If you have large pieces to laser cut or engrave, it’s best to have them in separate files. The laser bed is 1200 x 800mm, so keep each individual artwork file to that size as a maximum. Alternatively, you can use size of the sheet of material we plan to use if it’s smaller.

I have a few pages of artwork. How should I send them?

Separate pages in a pdf work well if you’d like to keep all the files in the same document.

Alternatively, a zip file with separate dxf, ai or pdf files is fine. Dropbox is a great option too. You can group several files in one project folder and share it with me.

Can I group artwork for different materials and thicknesses together?

No. It’s best to group artwork to be cut from the same material, thickness and colour together to minimise material waste. I will only process one sheet of material in the machine at a time.

You could have a file for 10mm clear,  one for 10mm white and one for 5mm red Perspex for instance. It makes it easier for us both and avoids confusion if each artwork file is named after the material, thickness and colour of the material to be cut if you have several.

Then I can cut everything from the same material specification together to maximise efficiency.

laser cut golf bag tags
Golf bag tags laser cut from 3mm plywood

Can I cut to the edges of the material?

I never use the edges of sheets of material as they’re often unfinished or have saw marks. For best results, it’s best to cut all the outlines of the shapes so they all look the same.

It’s best to buy materials with a 5mm margin on each side to make sure that this is possible. If it helps, you can show the outline shape of the material sheet in your artwork as a check that everything fits.

Should I have gaps between cut out shapes?

Yes, but 2mm is enough to avoid wasting material. We don’t want cut lines to be superimposed or too close to each other. It’s better to cut through material once only, or you get flaming and damage to the back of the material. Perspex and wood are flammable, so this is important!

Of course, if you just have a single shape that you want laser cut and engraved multiple times, I only need that artwork file. I can tile it in my software to get as many pieces as possible from the material. In the picture above, you can see the waste plywood remaining after cutting the golf bag tags for Holiday Essentials and Scotland Golf Tours.

If you have any questions that I haven’t answered, drop me a line at jane@laserflair.co.uk or give me a call and I’ll be happy to help.