Laser Cut Edges

[James Cogbill]

When I cut letters or shapes on my Trotec Speedy 300, I get an angled edge from the laser; any tips to remedy this?

[Mike Lassiter]

Focus is not correct is my thoughts. If kerf wider at the top than bottom try raising focus height and run some test cuts until you have sharpest thinnest kerf.

[Mike Null]

Is the material flat and in focus at all corner of the material?

A picture would help others help you.

[Dan Hintz]

When I cut letters or shapes on my Trotec Speedy 300, I get an angled edge from the laser; any tips to remedy this?

How thick is your material? You're always going to have an angled kerf, but it's not really noticeable until you start working with thicker materials (like 1/8" or greater). As mentioned, changing your focal point can help mitigate your perception of it, but it won't eliminate it (nature of the beast). If the material will allow it, try focusing into the material about 1/3rd of the way... this is a good compromise between having a high power density right at the face (and therefore a clean top edge) versus too much Z-height to show an angle.

[Gary Hair]

If you cut a square do the top and bottom (or left and right) edges slant the same way? like this - \ \ or are they opposite like this / \. If both are the same then you have an alignment issue, if they are opposite then it could be focus. Most likely if it's because of focus you'll see the angle on any edge whereas if it is alignment then you'll most likely only see it on two edges. An easy test would be to cut 1/4" thick clear acrylic and look at all four edges, the angles should be pretty obvious.

[Joe Pelonio]

The beam is actually hourglass shaped, so you will always get a light angle to it. As Dan said it's more on thicker materials. On 1/4" it will be obvious. If you need perfect 90 degree edge you will have to either use a CNC or run the pieces through a sander, and in the case of acrylic, flame polish it.

[Rich Harman]

I don't disagree with the above comments but I will add that it is possible to control the angle with cutting speed. For example, if you focus on the surface and cut too fast - so that it barely makes it through - you will have a wide kerf on the top and very narrow or nonexistent kerf on the bottom. Cut too slow and you will have a wider kerf on the bottom than the top. Cut at just the right speed and the top and bottom kerfs will be the same. Most of what I cut has no discernible angle to it.

I just went to the shop and grabbed these four scraps as an example:

284062

...and this is a scrap piece of 3/4" oak I cut recently, there is no angle at all to the cut:

284063

[donald bugansky]

80 watt cutting through 3/4 inch oak...... What am I doing wrong?

Bugs

Trotec Speedy 300 - 75 watt

[Dan Hintz]

80 watt cutting through 3/4 inch oak...... What am I doing wrong?

Not using a router? ;)

[donald bugansky]

Not using a router? ;)

Never thought about it that way. Maybe I'll forget the laser and stick with the bandsaw! ;)

i cant ant even get 1/2 inch to cut cleanly without a lot of attention and Loy's of praying.

[Rich Harman]

80 watt cutting through 3/4 inch oak...... What am I doing wrong?

Don't know... I cut that at about 3 or 4 mm/sec. Not something I would want to do very much of but a couple pieces now and then, works pretty good. I don't have a CNC router (yet) but even if I did, using the laser for this would have been a lot quicker to knock out.