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10 things you should know about laser cutting with Ponoko

Josh Judkins
posted this on April 15, 2013 18:37

Here are the 10 things that we think you should know about laser cutting with Ponoko - let us know what you would add!

1. How long it will take to make and ship your order.

We make all orders as quickly as we can, and how long that takes depends on the volume of orders we are processing at any one time. Due to the number of variables involved, we've written a separate post to help you work out the likely total time your order will take.
Read about our order timeframes.

2. If you are using Inkscape, you MUST use our design templates, or your design will be sized incorrectly.

We strongly recommend that everyone use our templates for laying out their laser cutting designs. If you are using Inkscape *it is 100% necessary*. The way that Inkscape works with measurements is different to other vector-based design software packages, and if you do not use our templates your parts will be made the wrong size. If you've already got an Inkscape design ready, we have created a guide to putting it on our templates.
Read how to place existing Inkscape designs onto our templates.

3. Our material sheets are larger than the usable white area of our templates.

The white 'safe area' inside the orange border of our templates is the guaranteed make-able area on our material sheets. We ensure that there is always a border of material around whatever you make.  That way none of your parts will run off the edge of the sheet and your parts will be better protected during shipping. Because of this, you must ensure ALL your design fits inside the orange border. This also means that if you want to make something with a straight, lasered edge, you need to add a blue cut line around the inside of the orange border of the template.
Read about adding cut lines to the outside of your design.

4. Material thickness can vary and is not guaranteed.

This possible variance is referred to as thickness tolerance. The thickness measurements we provide are the ones given to us by our material suppliers and manufacturers - who also specify a tolerance range +/-  a certain percentage. We have noted these % variations on the material catalog pages. Note that this variance makes designing interlocking laser cut projects challenging.
Read our advice for creating wooden interlocking laser cut designs.
Read our advice for creating acrylic interlocking laser cut designs.

5. The amount of material burned away by the laser can vary.

The amount of material burned or melted away by the laser is referred to as kerf width. Kerf width can vary due to a number of factors, such as:
         - variance in material thickness and density
         - whether the laser is cutting a horizontal, diagonal, or curved line
         - where on the sheet the laser is cutting, due to variations in the optics as it moves around
As such, there is a limit to how precise your measurements can be when using laser cutting. Although laser cutting is fantastic for a huge variety of projects, it's not the most appropriate if you need EXACT sizing.

6. If you place two cut lines too close together, there may be little or no material left between them.

As mentioned above, every time the laser cuts a line an amount of material is removed from each side of the line you have drawn. This means that any areas in your design where cutting lines come closer together than 0.5mm could potentially be burned away entirely, and any places where they are narrower than 1mm are likely to be quite fragile. A good way to spot these is to change your line weights to 0.2mm and print your design out on paper - in which case you'll see how much material will likely be left between your cuts.
Read about how this effects the placement of holes on the edges of your pieces.

7. Every cut line and vector engraving line in your file will be made by the laser.

You should ensure that only the vector line information NEEDED to make your design is present in your file. You never want to try and hide cut lines or vector engraving lines behind fills - they will be made by the laser-cutter whether visible in 'Preview' mode or not.

8. Raster fill engraving takes a long time, and can substantially add to your making cost.

Raster fill engraving is often the most time consuming part of a design because the laser must pass over the filled area many times to engrave it. When you do use raster fill engraving, it's best to keep all of your raster fill engraved areas as close together as possible. This is because the head of the laser will have to pass over the gaps between the areas to be engraved on the same horizontal line many times before the job is done. This can unnecessarily increase your making time and cost.

9. Very small parts (5mm/0.197" round/square and smaller) can fall through the laser bed during cutting and be lost.

When we cut your design, your sheet of material sits upon a honeycomb-like bed. This structure holds up the material without heating up too much so that it burns the back of the sheet. What this means, however, is that very tiny pieces smaller than 5mm round/square can fall through the honeycomb bed during the cutting process. This is something that cannot be avoided, so your best option is to add extra tiny elements to your design to account for those which may be lost.

10. The laser cutter will ignore 'dashed line' effects - so you need to ensure they're formatted right.

All our supported vector-based software packages have the ability to add a 'dashed line' effect to lines in your design. Unfortunately, this effect on its own is only for looks, and if you view your design in Outline mode, you'll see that the dashes are not genuine vector information. As a result, if you want to include dashed lines in your design, you'll need to either create them by either:
         - adding lots of nodes/anchor points to your line and manually removing every other segment, or
         - using a thicker line with the 'dashed line' effect, expanding it into small filled segments, and using raster fill engraving
Read more about creating correctly formatted dashed lines.