Nose cone clearance on Trotec Speedy 300 with 2.5" lens

[Lewis James]

We're currently looking at replacing our old Epilog Helix with a Trotec Speedy 300.

One of the jobs we use the laser for is cutting self adhesive foam gaskets after they've been applied to the inside of machined aluminium enclosures.

For this job we require 25mm clearance under the laser head to get over the sides of the aluminium enclosure.
At the moment I can just squeeze it in if I remove the air assist tube on the Epilog.
Unfortunately with the air assist gone we get a lot of flames and soot during cutting.

We'd like to use a 2.5" lens on the Trotec to get extra clearance while still having air assist.
The manual for the Speedy 300 states:
Caution: When working with the 2.5” lens the standard nose cone MUST NOT be used, as the diameter of the hole is too small to let the beam through. Use no or the longer 2.5” nose cone.

I haven't been able to find any details about the size of this longer nose cone.
Has anybody got the 2.5" lens and the longer nose cone?
Can someone please measure the clearance from the bottom of the nose cone to the workpiece when using the longer nose cone.

The alternative is to modify a standard nose cone with a larger hole.
Would this still provide an effective amount of air at the focal point?

[Jon Colley]

This type of job can be done on a Speedy 300 by changing the machine homing setting in Job Control. You can focus to the gasket and then set this to "No moves" so it doesn't go to home and collide with the enclosure at the beginning and end of the job.

You could also make this more automatic and reliable by putting a zero power short move as red to bring the head past the edge of the enclosure. The cut pass could be run as blue with a negative Z-offset to bring it up into focus and then another zero power move on green at the standard zero z-offset would bring it back down so that it clears the enclosure at the end of the job. This is more of en "expert level" method of doing it though, as you would need to modify the maximum for negative Z-offsets if this offset is higher than 5mm.

Jon

[Scott Shepherd]

Just use the other nose cone. The machines come with 2, 1 is for the 2" lens, which has a small hole and the second one has a large hole and you can use it with 2.5" and 4" lenses. The statement is just saying not to use the one with the small hole on the 2" lens because it'll hit the edge of the nose cone.

[Lewis James]

Thanks for the ideas.

I hadn't realised we could inorporate Z movements into a job with the Trotec.
For this particlar part we still need the clearance as we have to cut very close to the enclosure wall, but it may be of use on other products.

I've sent some sample gasket material to our Trotec dealer to try out with the 2.5" lens and nose cone to see how effective the air assist is from a longer distance.