We can engraved curved surfaces as well as flat ones, but it depends on the curve and the material. Here’s an example.
We engraved these beautiful beech coffee tamper handles for Made by Knock for their customer, Machina Espresso. They’re so tactile, and are perfect for engraving if you can work with the curved surface. That was the biggest challenge, along with getting the logo centred on the top. You can easily spot if engravings are out by a millimetre.
It’s all about focus
The principle is that flat surfaces should be engraved. This is because the laser beam is focussed vertically onto a horizontal surface. The distance between the lens and the material surface is crucial for high quality engraving. Lenses have specific focal lengths that should be adhered to for best results. Even a tolerance of plus or minus 1mm can be a problem depending on the material used and the lens selected.
These principles need to be adhered to more for sensitive materials like acrylic and metal where a reduction in engraving quality is very easy to spot. Wood, on the other hand, is much more forgiving.
My secret weapon
My secret weapon is my 100mm lens. It allows me to work with a curve of around 8mm, particularly if the material is forgiving like wood is. I’ve used it to engrave these tamper handles and mini wooden baseball bat muddlers for mixing cocktails. It is still important to keep engravings on relatively flat areas for best results.
Before we went into production, we engraved Machina Espresso’s logo on a few tamper handle seconds to judge the largest size the logo could be engraved to keep the logos on the flattest part of the handles. It was important to know at what size engraving quality would deteriorate, and to make sure that engraving results would be consistently high quality.
Glenmore Lodge National Outdoor Training Centre near Aviemore had designed and were creating a new garden for their facilities. It was felt that a training centre would benefit from having an outdoor space to encourage personal reflection.
They approached LaserFlair with the idea of creating a wooden ‘library’ consisting of oak ‘books’ to create a focal point. To add an element of fun, they wanted titles relevent to outdoor activities engraved on their spines. My favourite was Classic Rock.
How to make an outdoor wooden library
Glenmore Lodge provided a list of the titles they wanted engraved on the oak books. They cut the wood into blocks of different shapes and sizes to simulate a shelf of assorted books. Each book was shaped to give the impression of a spine along one side
LaserFlair advised on fonts and layout to get the look and depth of engrave for the right look. We chose a bold font for the text to make it easy to read from a distance, and made the text as large as possible to fit the width of the books’ spines. We decided on a deep engrave for a lasting appearance and texture as the books were designed to be touched and weather with the garden.
Laser engraving the books
Each block of oak was positioned in the machine so that the ‘spine’ was uppermost. We do this because the laser head is aligned vertically and engraves the horizontal surface below. We lowered the machine bed by 15-20cm so that each ‘book’ could be positioned at the correct focal distance from the lens. Maintaining focus is important to achieve good engraving quality. Finally, we raster engraved to create a pleasing 3D effect, and performed two passes to give extra depth to the letters.
Glenmore Lodge love their new garden feature. It gives a sense of intrigue and intimacy.
Customers request all sorts of weird and wonderful commissions. Customers have lovely ideas to personalise gifts that are only limited by their imaginations, so no two jobs are ever the same.
A customer approached us to ask if we could engrave a pair of matching wooden tankards. He’d commissioned them as gifts for friends for their festival themed wedding or ‘wedfest’. If possible, he wanted to personalise them to make them extra special. Perhaps they would become family heirlooms to be treasured for years to come.
Engraving cylindrical objects
It is possible to engrave cylindrical objects, but this has its challenges. The laser needs a flat surface to focus on for best results. If the laser beam loses focus, engraving quality suffers and becomes fuzzier. The more out of focus the beam becomes, the worse the effect is.
We suggested that for something a little different and to maximise the chances of success, we could engrave the tankards vertically. This tactic would allow the laser to focus on the relatively flat spine of the cylinder. It worked a treat and you can see the results in the photo.
Top tips for engraving cylinders
We used our 100mm focal length lens to compensate for the slight curve on the circumference of the tankards. We performed a nice deep raster engrave to give a 3D effect on them, and the look really suited the chunky tankards. My customer was delighted with the results.
You’d assume that 3mm plywood is 3mm thick, wouldn’t you?
Wrong! With plywood, thicknesses are nominal, not actual. This is because plywood is made up of different layers glued together. 3mm usually has 3 layers, and the result is an actual thickness of 3.2-3.3mm. 4mm ply has another layer, and is usually 3.8mm thick.
Potential design disasters
This can create a whole worlds of pain for designers and manufacturers if they want to create products made up of pieces that slot into each other and require a good fit.
If you assume a thickness of 3mm and you design 3mm slots in artwork and then try to fit 3.3mm thick wood in the slot, it’s not going to happen. Or if 4mm ply were used, 3.8mm parts would be too loose.
Imagine making 300 reindeer kits for Christmas, sending the artwork to a maker, and getting back parts that don’t fit?
This could have happened to one of our earliest customers, but we made a prototype, realised the problem and fed it back to the customer. They tweaked the artwork before we performed the production run. This simple check saved our customer – and us too – a lot of time, money and heartache.
Always check that your designer and maker are speaking to each other to avoid disasters like this.
I love these wooden rings! But when Waiata Bespoke Jewellery (nga waiata as they were then) first got in touch and asked if I could engrave the backs of their chunky wooden rings with their logo, I wasn’t sure if I could do it.
Engraving on a curve
First of all, rings are cylindrical. Lasers need a flat surface to engrave. This is to maintain the right focal length for the laser beam for best results.
Secondly, the rings have such knobbly stones on them and nga waiata wanted to supply them made up rather than without the stones. How could we support them securely in the laser so they wouldn’t wobble or fall over during engraving? Any of these scenarios would be disastrous for engraving quality.
It’s amazing what you can do with Blu Tac! I use it all the time to support jobs on the machine. A nice big blob on the engraving bed floor held each ring securely, even although the stones are all different shapes.
My secret weapon
Now for the engraving. The text was small and fine and was to be centred in the middle of each ring back. I used my longest focal length lens which helps maintain focus better over curved surfaces. I also slowed the engraving speed down to maximise precision and minimise any wobble from the machine. This ensured crisply engraved letters, with a nice depth of engraving to give good visual impact in the chunky wood.
Yesterday, a customer asked me if I can make laser cut wood edges as black as possible as it would enhance her products. She wanted this even if it caused some charring on the surface which could be sanded off. No other customers had asked for this before. They just accepted that the edges would look as they came, and I would prepare them for what to expect.
The colour of a laser cut wooden edge is more to do with the colour of the wood used. A pale wood like birch or sycamore will have a lighter cut edge. Oak will be darker and mahogany darkest of all.
Best machine settings for laser cutting wood
The golden rule of laser cutting is to cut through cleanly in one pass as quickly as possible with a maximum of 90% power. This should minimise damage to the material and maximise product quality. If you cut more slowly than you need to, you don’t get a darker edge. You just get charring and flaming on the back of the wood. And it’s possible that the flaming could ignite the wood and cause a fire in the laser machine.
In this case, all the woods from plum to sycamore had quite dark laser cut edges. Kirsty makes wooden jewellery from the tiny shapes and sometimes paints them. You can find her as Hamespuns on Instagram.