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.

are vector and raster engraving different

Are vector and raster engraving different?

Posted Posted in FAQ

There are big differences between vector and raster engraving. They are created by the same machine in different ways and give very different results using the same artwork. So when you’re thinking about your project, you need to think not just about the look of the product, but what your budget is. Raster engraving usually takes longer and therefore costs more than vector engraving.

In the image above, you can see that the top image was created using raster engraving and the one below with vector engraving.

How vector and raster engraving are created

Raster engraving is created by the laser scanning the engraved areas very much as a printer does, filling the area to be engraved line by line.

Vector engraving, on the other hand, is created more like a line drawing. The laser follows the vector lines and draws them as a single line. The video below shows this clearly on oak.

How do vector and raster engraving look?

Vector engraving looks much finer than raster engraving and is only a line thick. It’s best used where there’s a lot of fine detail that might get lost with raster engraving. It worked really well on these robin decorations by Jenna Chalmers and the Celtic lion shown on the Artwork Preparation Tips page of my website. Both pieces have very fine detail that shows up most clearly when engraved with this method.

vector engraved robin decorations

What vector engraving makes up for in well defined detail, it lacks in boldness. It’s perfect for small items, and is best seen at close quarters. It’s perfect for decorative work and for packing lots of detail into areas large and small.

Raster engraving, on the other hand, works better for bolder artwork with less very fine detail. It can be more 3D too as the engraved areas are recessed on materials like wood. It’s more suitable for signs than vector engraving, but it works just as well for coasters and branded presentation boxes. I use it on my business cards as there’s more contrast between the text and the pale birch plywood that the cards are made of.

 

Do you have a questions about laser cutting or engraving and how it might affect your project? Contact us with your questions and I’ll write a blog about it.

laser cutting and engraving knots in wood

Laser cutting and engraving knots in wood

Posted Posted in FAQ, Wood

Laser cutting wood creates some very beautiful effects. One of the beauties of wood is its grain, and knots are a part of these growth patterns, but knots can present some production challenges too.

What is a knot?

Knots are found at the bases of side branches in trees.  Lower branches often die. As the girth of a tree expands, the trunk envelopes them, forming the imperfections we know as knots.

Beautiful as these imperfections are, the wood in those areas is much denser than the surrounding wood. It’s this difference in density that can cause issues.

How do knots affect laser cutting?

Denser wood is harder to cut and needs a slower cutting speed to cut through cleanly. If I cut 3mm ply at my usual speed, this is fine for most of the sheet of ply, but if the laser beam hits a knot, the chances are it will be going too fast to cut through the knot effectively. This is clearly shown by the 9mm ply ampersand at the top. Two knots prevented a clean cut through to allow the middle piece to fall out cleanly.

This means that the cut through won’t be clean in the area of the knot, and the item won’t separate from the sheet and won’t be of sufficient quality to be sold. If the wood is solid like oak, you can see where all the knots are. In plywood, however, there are knots in the middle layers that you can’t see. You can see the star below made of 6mm ply had one of these, and the knot caused the telltale puff of black dirt on the surface of the wood that can be sanded off.

As a rule, the more knots there are in a piece of wood, the higher you can expect the failure rate of laser cut items to be.

laser cut star with knot

How do they affect laser engraving?

Knots don’t cause so many problems with engraving. You can expect to see any engraving over them to be shallower than on the rest of the wood. Knots are denser so engraving depth is compromised, but the effect is still easily seen. The knot shown above is under the n and t of adventure,

If the artwork is vectorised, it’s possible that the sections over the knot can be engraved more times to achieve more depth to compensate.

laser engraving over a knot

Do you have a questions about laser cutting or engraving and how it might affect your project? Contact us with your questions and I’ll write a blog about it.

How do the edges of laser cut wood look

How do the edges of laser cut wood look?

Posted Posted in FAQ, Materials, Wood

Customers sometimes ask me what laser cut edges of materials will look like when they’re thinking about how their end products will look.

Wood is an interesting material. The look of the cut edges depends on the wood itself and its thickness. Solid wood, laser plywood and mdf all give very different results.

Solid wood

Most solid woods cut well. Oak is one I work with a lot. Max McCance, a local furniture maker, rips up batons of oak for me to make items including coasters for Welsh Oak Frame and Arboreta.

Oak yields a consistently dark laser cut edge. One particularly attractive feature is that the wood grain can be seen across the cut. It’s different on each coaster as wood grain is different, even if the wood is from the same part on the same tree. You can see this in the picture above.

Cut edges of other solid woods can look different. Some are more dense than others and wood grain is characteristic to each wood. As a general rule, the darker the wood, the darker the laser cut edge. Wood thickness can affect this too. And thicker the wood, the slower it must be cut and the darker the edges can look.

laser cut ply edges

Laser plywood

The laser ply I use is birch, a very pale wood. I source it in thicknesses from 3 to 9mm. Plywood is made up of layers glued together, around three for 3 and 4mm ply and five for 6mm ply. Laser cut edges show up these layers as you can see in the picture below showing my 3mm business card, and 4 and 6mm stars for InkPaintPaper.

I can cut 3mm ply much faster than 9mm ply. And the edges look very different. 3mm edges are golden brown, as are 4mm edges. 5 and 6mm edges are much darker, and 9mm edges are close to black.

 

Mdf

Mdf is much a much darker board and I can up to 9mm mdf. Laser cut edges on 2 and 3mm mdf are brown and 6 and 9mm mdf edges are black. The pony above is cut from 9mm mdf for PinkFishShetland.

As mdf is a homogeneous board, there is no texture or layer structure visible on the cut edges.

 

Have you got a project that you think we could help you with? Contact us or ask for a quote.