In the Air Tonight

[Christopher Long 1]

I just watched your presentation - very good and interesting. However, unless I missed it you didn't mention applying a kerf - do you do this, and if so do you apply it to the dxf files or do you use Liteburn to apply the kerf, oh and what do you set the kerf to?

[Ron Gray]

Ok so for those who don't know what a kerf is - if you are cutting say with a router then the tool you are using has a diameter therefore to get the cut line correct you have to apply an offset or kerf, another analogy would be a handsaw blade, you cut to the outside or inside of a line not on it. With my Sculpfun it has a laser light of approx 0.08mm diameter so tbh I don't bother applying a kerf as even finger joints are excellent! However if I was going to apply a keg then Lightburn has that built into the properties of a cut (a negative would be inside, positive outside):

 

 

 

[Ron Gray]

As promised here is my shop setup of my Sculpfun

 

 

[Ace]

Thanks, interesting, informative and well presented just as your ITAT talk was 👏

[leccyflyer]

Fantastic run through Ron- all really well thought through and implemented. You've got that working beautifully and a proper practical set up. Thank you so much for putting that together and sharing it. I'm completely hooked. 😄

[Ron Gray]

@leccyflyergo for it, for the under £1K outlay it's brilliant value for money!

[leccyflyer]

Yep, I see one of those very useful machines in my future, for sure, thanks to your inspiration,

[Ron Gray]

its another one of those bits of kit that you wonder how you managed without it!

[Mark Turner 12]

Here’s another take on it , this might dovetail nicely into next weeks itat on cnc routers.  

 

[Andy Symons - BMFA]

News of the next In the Air Tonight session on Tuesday 14th March and also a general In the Air Tonight update can be found at https://itat.bmfa.uk/news

[Ron Gray]

I'm doing a follow up session tonight, Fusion 360 - wing rib set production for laser cutting.

[leccyflyer]

It was brilliant Ron - really enjoyed it.😎

[Ron Gray]

Thanks for that @leccyflyer

[Ace]

Nice one Ron. 👏

Couldn't make the live stream but just watched it on You Tube. Interesting, informative and well presented in lay mans terms if a little beyond my capabilities.

Well worth a watch if only to see how a laser cut set of ribs is prepared for cutting.

[Ron Gray]

Thanks Ace, glad you enjoyed it. TBH it looks daunting but it really isn’t, the trick is to understand the workflow and then to use the relevant tools to achieve it. And whilst I’ve only been showing working in Fusion 360 other software is available to do the same. It’s Fusion 360 for me because I have a paid for version!

[Ron Gray]

If there’s enough interest I’m happy to take this a stage further and show how I would create a rib set for a Spitfire wing complete with washout, now that really does take a bit of head scratching to develop the workflow and involves 3D sketching!!!

[Barnstormer 52]

Hi Ron

 

Found Tuesday session on wing ribs very helpful.

 

I have used Fusion 360 before for making Tx case parts for a 2.4ghz conversion.

 

I have worked through the stages as per Tuesday's session up to the point of 'Arranging' the ribs just prior to Exporting them in a dxf.

 

The 'Arrange' feature in 'Manufacturing' is greyed out in the hobbyist free version and is only included in the 'paid for' version - is ther a work around?

 

Many thanks

Geoff

[Martin Gay]

Geoff,

Have a look at this youtube video from Terrance at RC CAD 2 VR

 

The rest of his videos are very good learning tools as well!

 

Martin.

[Ron Gray]

Thanks for putting that there Martin, his series of vids are really good.

 

@Barnstormer 52for the 'free' version of Fusion 360 you will need an add in (shown in the above vid too!), it's called DXF for Laser and when installed will give you the option to select the parts that you want and to save them as DXF files. I've not used it myself but it looks straightforward, I would suggest that you don't need the nesting tool mentioned in the above vid unless you are doing a lot of parts, the nesting output in Lightburn is OK, not brilliant, but most of the time I nest the parts myself!

 

Download the add-in from the Autodesk store.

[Martin Gay]

All,

 

I also found the youtube videos on Val's Puzzle Planes to be very useful. There is no talking on these videos so you have to have some idea of what is going on, but I used his single seat SU-25 tutorials to draw up a twin seat version for myself.

 

 

I can also recommend the Fusion 360 training from Armada.co.uk. They are not exactly cheap but they taught me a lot after I had been struggling to learn Fusion 360 on my own.

[Ron Gray]

If you want a great YouTube range of tutorials I find that PDO is hard to beat, easy to understand steps and very up to date with the latest product updates

 

 

[Barnstormer 52]

Ron, Martin

Thank you - have both of those now and have moved on a bit.

Geoff

[Ron Gray]

👍

[leccyflyer]

Since being enthused by Ron Gray's BMFA In The Air Tonight webinars on laser cutting and CAD I took the plunge a few weeks ago and shamelessly copied Ron's set up for a budget, pretty much ready made diode laser cutter. The machine is a Sculpfun S30, which houses a 20w blue diode laser and I opted for the extended Y axis conversion which is claimed to extend the reach of the machine to 440mm x 945mm, but actually gives a usable cutting area of 390mm x around 890mm.

In discussions with Ron and others it became obvious that I wouldn't be able to install such a machine in my workshop and that I'd need some system for collecting and exhausting the smoke produced during cutting, to the outside world. That meant the machine would live in the barn/model store area, so would need protecting from dust and debris, plus that smoke extraction and I was also quite keen to have some form of safety filtering for reflected laser light. Sculpfun do a 1400mm x720mm enclosure for the laser cutter so that looked ideal. I assembled the enclosure first, as that would be needed to keep the cutter safe from airborne debris in the barn.

Next issue was that the floor in the barn dips alarmingly towards the door - which is a good thing in the event of flooding - and I wanted to have the laser cutter pretty level - it also wanted fixing to a sturdy baseboard. I have copious volumes of ply offcuts from the workshop construction, but the only piece large enough was horribly warped, so I had to bring in a slab of 18mm ply. Positioning the table in the optimum position showed that the board needed jacking up along the downdip end, by the thickness of one of the other ply offcuts, which was good.

Ron kindly provided me with files for 3D printing some feet for the frame and everything fitted together in a reasonably short timeframe - there are decent assembly and setup videos on Sculpfun's You Tube channel. There are a few wrinkles involved in the assembly, but it was fairly drama free. Cable management and the routing of the air assist "trachea" are the main things and it remains to be seen how well that works out. I've left sufficient room on the table for the laptop to sit at the corner of the machine, next to the control box.

The recommendation is to use the honeycomb frames which allow air assist of the cutting - these are in the form of two 405mm square assemblies which have a separate sheet of 0.5mm aluminium to sit underneath the honeycomb. As I was using two of these for the extended platform, I opted to use a single 1000mmx500mmx0.5mm aluminium sheet which also protected the ply board between the honeycomb units. They rest on 4mm thick slats, which leave a gap through which the smoke system should be able to pull the smoky air away from the laser at the workpiece. That's the theory anyway.

The end and side panels of the enclosure are removable to place the workpiece in position on the honeycomb bed(s) - then they get put back to complete the enclosure during cutting. The ducting from the fan at the rear of the enclosure will exit through a vent that I'll need to cut in the barn door. It'll only be connected whilst cutting, the vent will be blocked with a plate the rest of the time. I didn't really want to cut a hole, but it 's a better option than to try to cut through eighteen inches of Old Red Sandstone, which is a non-starter. There's space on the table to completely remove the enclosure if desired when securing the material to the cutting base - which is accomplished with small 3D printed pegs which engage in the honeycomb structure and hold the sheet material in place.

Last job, which I haven't done yet is to set the origin point for the cutter exactly. At that point I can screw down the slats on the honeycombs to the base and it should all be nice and rigidly fixed in place.

The main job in hand for the cutter is cutting Depron for SEMFF fighters and Parkjets, a bit of balsa cutting to recreate a few models from my past, some engraving of data plates and notices for a couple of projects and there's bound to be other things that turn up. Mostly it's about learning something new though- and the learning curve looks quite steep.

 

I'd just like to thank Ron for the inmpetus to embark on this project and for the help and assistance he's given in answering my very basic questions during the process. Thanks Ron - you're an inspiration Sir!

 

 

Edited May 8, 2023 by leccyflyer
Got a number wrong!

[Ron Gray]

Excellent setup. I also recommend having a look at the YouTube vids done by Rich (TheLouisianaHobbyGuy) and go onto his forum as he has lots of useful information on there about using Lightburn.

 

 

Edited May 8, 2023 by Ron Gray