Laser Cut chassis kit

Hi all,

I've been playing with a Monport fibre laser recently and though my most recent experiment might be of interest to some.
The pictures show my first attempt at producing an etched chassis kit using a laser machine.
There are some tweaks to make, and some redesigning of the 3d printed body to do, but I think the results are quite encouraging.
There's also the bogie to do, but I've not made my mind up on the best form of springing for it just yet.


It's for an SE&CR F class, eventually it will become a B, B1 & an F1 too.

It looks as though the structure isn't square in this image, I think that's a photo thing, as it's quite true when measured-up. Also, the bogie stretcher isn't fitted here.

 

[Martin Wynne]

an etched chassis kit using a laser machine

@James Walters

Hi James,

Looks great.

Just to clarify, there is no chemical etching?

So it's not an "etched chassis kit" in the usual meaning?

We need some new terminology.

Having discovered free Kiri:Moto, it should be equally possible on my CNC miller.

cheers,

Martin.

 

[James Walters]

Exactly, no chemicals were harmed in the process.
I used the term 'etched kit' as I was experimenting to see whether or not it would be possible to reproduce the outcome of a chemical etching process with a laser. It seems that you can.

 

[Penrhos1920]

So you're using a laser cutter to cut out brass pieces? What's the wattage of the laser? Is there anything special about the brass like an anti-reflective paint?

 

[Terry Downes]

So you're using a laser cutter to cut out brass pieces? What's the wattage of the laser? Is there anything special about the brass like an anti-reflective paint?

Hi James, I have been considering purchasing a fibre laser to laser cut thin (0.2 to say 0.5mm) steel sheet but, I just can't believe some of the specifications and want to see/try results etc before purchasing. Can You provide some info regarding the fibre laser You are using e.g. wattage etc as well as the material steel? plated brass?
Terry.

 

[Martin Wynne]

.
I don't know which Monpot fibre laser James is using, but this ComMarker video appeared on my screen recently. The spec says max metal cut 0.3mm:

ComMarker: https://commarker.com

Monpot: https://monportlaser.uk/collections/fiber-laser-engravers

Martin.

 

[James Walters]

So you're using a laser cutter to cut out brass pieces? What's the wattage of the laser? Is there anything special about the brass like an anti-reflective paint?

I've been cutting and engraving brass, nickel silver and stainless steel. I'm using a fibre laser which will process metals, and no special coatings are required.
It's an engraver really, so it requires lots of passes to cut, about 20 at 100mm/s to cut through 0.45 nickel silver.

 

[James Walters]

Hi James, I have been considering purchasing a fibre laser to laser cut thin (0.2 to say 0.5mm) steel sheet but, I just can't believe some of the specifications and want to see/try results etc before purchasing. Can You provide some info regarding the fibre laser You are using e.g. wattage etc as well as the material steel? plated brass?
Terry.

Hi Terry,
I'll provide some detailed cutting and engraving information once I'm confident that I'm using the machine optimally. But basically, it's a 30W MOPA fibre laser. I've cut through 2mm brass, but it took lots of passes (possibly 150), but it's very quick cutting efficiently at about 100mm/s. So far I've worked on engraving and cutting brass, nickel silver and stainless steel. I think it will work with most materials, and should be very good at engraving plastics.
The downside is that there are essentially 4 parameters to control, as opposed to the 2 of say a diode or CO2 laser. Mastering them will take me some time.

 

[James Walters]

.
I don't know which Monpot fibre laser James is using, but this ComMarker video appeared on my screen recently. The spec says max metal cut 0.3mm:

ComMarker: https://commarker.com

Monpot: https://monportlaser.uk/collections/fiber-laser-engravers

Martin.

I think that would be 0.3mm/pass.
These machines lightning fast though, I was engraving some aluminium business cards today at 2500mm/sec.

 

[Martin Wynne]

Hi Terry,
I'll provide some detailed cutting and engraving information once I'm confident that I'm using the machine optimally. But basically, it's a 30W MOPA fibre laser. I've cut through 2mm brass, but it took lots of passes (possibly 150), but it's very quick cutting efficiently at about 100mm/s. So far I've worked on engraving and cutting brass, nickel silver and stainless steel. I think it will work with most materials, and should be very good at engraving plastics.
The downside is that there are essentially 4 parameters to control, as opposed to the 2 of say a diode or CO2 laser. Mastering them will take me some time.

@James Walters

Hi James,

If there is a single lens, rather than a moving head, presumably cut edges near the edge of the bed will be angled? While cut edges near the centre will be vertical?

What are the health hazards from the metal fumes? For example some alloys contain lead.

cheers,

Martin.

 

[James Walters]

That's right, a single lens through which the laser is guided by two mirrors which move to control X and Y movement.
The focal length is close to 400mm, and the cutting space with the lens I currently have fitted is 175x175mm, so the angled cut at the edges would theoretically be about 13 degrees. But the laser looses power towards the edges so I doubt one would be able to cut something of sufficient thickness for the angled cut to be perceptible. Cuts near the centre are indeed vertical.
Extraction is a must, but the vapourised material is very light, and a small computer fan is sufficient to remove any solid particles, as for fumes I intend to build an enclosure for the machine should I be allowed to keep it following testing it out.
It's a lovely piece of equipment, but way out of my personal budget so I'm trying not to fall in love with it just yet.

 

[Phil G]

@James Walters

but way out of my personal budget

And there lies the big problem Do you have a UK retail price James? I priced one at 2.5K the other week and decided good as it looks thats much much for me. Do for you that you get to keep it.
Terry did you get as far as pricing. So are going to do a lot of YouTubes videos on this one James
Also is there any sign of metal distortion, . on say the Nickel silver? which I an guessing will be a bit more prone than Brass?. Given it a bit harder to saw thought.
It looks for the photos as though the side frames are a bit bowed out at the stream chest. That could also be down to the steam chest fit not be snugged up yet, of course.
cheers
Phil

 

[Phil G]

Just a quick correction, it was the Raycus 30W that was at 2.5K. The JPT Mopa M7 30W was 4.6K
you would have to do a whole lot of metal cutting chassis to get your money back on that one.

cheers
phil,

 

[Martin Wynne]

And there lies the big problem Do you have a UK retail price James? I priced one at 2.5K the other week and decided good as it looks thats much much for me.

@Phil G

UK prices for the one in the video:

20W £1280 https://www.amazon.co.uk/dp/B0C49K4W35

30W £1780 https://www.amazon.co.uk/dp/B0CRTKRQPL

Or £370 for one of these if you are more interested in cutting thin metal than marking it:

https://www.amazon.co.uk/dp/B0BGLC3R1D

Which can also do 2.5D pocket milling, e.g. for plug track timbering bricks as an alternative to FDM printing. It would also make the filing jigs in hardwood (drill the bolt holes separately with a power drill).

Martin.

 

[James Walters]

@James Walters

And there lies the big problem Do you have a UK retail price James? I priced one at 2.5K the other week and decided good as it looks thats much much for me. Do for you that you get to keep it.
Terry did you get as far as pricing. So are going to do a lot of YouTubes videos on this one James
Also is there any sign of metal distortion, . on say the Nickel silver? which I an guessing will be a bit more prone than Brass?. Given it a bit harder to saw thought.
It looks for the photos as though the side frames are a bit bowed out at the stream chest. That could also be down to the steam chest fit not be snugged up yet, of course.
cheers
Phil

Agreed, very expensive. This particular machine is £3.5K. I'm not suggesting anyone should buy one (I'm only testing it out myself out of an interest in understanding the technology), but it's another option for one to take to a bureau just as many do for other laser cutting jobs.
My interest lies in that whilst I have chemical etching equipment, the chemicals go-off quite quickly so I tend to save-up etching jobs to do all at once. I think that for prototyping this is an excellent alternative. If I were to replace my chemical etching equipment at todays prices I could probably buy 3 of these fibre lasers. I expect the prices to tumble soon as they have done for CO2 and diode lasers, unbranded equivalents on AliExpress can be had much more affordably.

Yes, distortion is a problem. It's avoidable by going nice and slow but requires decent workholding to minimise. I have a ordered a sheet metal vice designed for such tasks which I think will improve the situation.

Re. the bowing by the cylinder stretchers, there is a slight distortion here as I made the stretchers a little too wide.
I'll remake them for the V2.

 

[James Walters]

@Phil G

UK prices for the one in the video:

20W £1280 https://www.amazon.co.uk/dp/B0C49K4W35

30W £1780 https://www.amazon.co.uk/dp/B0CRTKRQPL

Or £370 for one of these if you are more interested in cutting thin metal than marking it:

https://www.amazon.co.uk/dp/B0BGLC3R1D

Which can also do 2.5D pocket milling, e.g. for plug track timbering bricks as an alternative to FDM printing. It would also make the filing jigs in hardwood (drill the bolt holes separately with a power drill).

Martin.

I use a Roland equivalent of one of these at work to cut brass and the noise does my head in.
They're great machines though, I used to keep one engraving PCB's all day in a previous job before the laser turned up.

 

[Phil G]

Hi James,
yes I do agree with you, its very useful for prototyping. Unless the price does drop quite I bit its sill going to be outside the price range of hobbyist. I would think its even outside the price bracket of a club.

I am still very much looking forward to your videos covering this piece of equipment thought.

Out of interest how do you think it would do at doing w irons? ones that could drop into a premade slot in say a resin printed wagon, if that works it opens up the ability of making a composite wagons using Brass/Nickel Silver for the thin pieces. which would have been 3/4" thick iron plates on the prototype. So would be almost dead scale at 10 thou Nickel silver..
Just another thought to put out there?
cheers
Phil

 

[Martin Wynne]

I use a Roland equivalent of one of these at work to cut brass and the noise does my head in.

@James Walters

I agree about the noise. The high spindle speed and lightweight construction makes the desktop CNCs very noisy. It's worth finding or making a thick wooden box to put over it, once you are happy to leave it running for a few minutes.

And the Klipper-based FDMs are not quiet with the extra fans running. The little Kingroons are much quieter.

Martin.

 

[James Walters]

Hi Phil,
Good question, I've made several already to suit my own wagons and they work perfectly just like a Bill Bedford example.
It's been brilliant for brake gear also, especially the pin-down hanger (can't remember the correct name), I just cant get those to print as well as I'd like to save my life.
It is also capable of etching in 3d from a depth map. So, taking a smokebox door for example, one can convert a .stl file into a depth map (or greyscale .png), and lightburn will effectively slice it and over the course of say 200 layers etch out the 3d shape including hinge straps, centre box, shed plate, etc. I'm still learning how to do this properly, and haven't had much success yet, but I'll get there.
Surface finishes can be excellent as the machine can be set to scan at many thousands of lines per inch, 0.003mm for example.
This cannot be done on a diode laser, and isn't brilliant on a CO2 laser which is limited by a (relatively) massive spot size.

 

[Phil G]

especially the pin-down hanger (can't remember the correct name),

Are you talking about the break lever guard assy. The ones with all the holes or saw tooth rack, to pin down the break lever when applying the hand breaks?
If so I agree these and the safety strips don't look quite right when you have to thicken them up for resin printing.
any change you could have a crack and laser cutting a set for a RCH 1923 std wagon?
Cheers
Phil

 

[Phil G]

@James Walters
Just a left field question what angle do you print your MR coal wagons at on the printer? and do you use a lot of supports?
cheers
Phil,

 

[James Walters]

@James Walters
Just a left field question what angle do you print your MR coal wagons at on the printer? and do you use a lot of supports?
cheers
Phil,

Hi Phil,

This is how I print them, a 0.8mm plywood panel with the engraved planking drops in from the top and fixes to the solebars which protrude into the space a little.

As for 1923 RCH brake lever guards (thank you for the correct term), I could have a look at them. I have the drawings. I'll add it to my long to-do list.

 

[Martin Wynne]

Hi Phil,

This is how I print them, a 0.8mm plywood panel with the engraved planking drops in from the top and fixes to the solebars which protrude into the space a little.
View attachment 10602

As for 1923 RCH brake lever guards (thank you for the correct term), I could have a look at them. I have the drawings. I'll add it to my long to-do list.

Hmm.

1. I have two resin printers.

2. if I build 47S I will need some wagons.

The snag is that all my time is taken up with Templot. At present there's a battle going on between Lazarus and EMF, and it's not clear which is winning.

Martin.

 

[Phil G]

2. if I build 47S I will need some wagons.

Hi Martin,
Once I have it finished to my satisfaction, I would be happy to put a STL of a 4mm 1923 7plank wooden underframe wagon on the resource page.
My thinking is to take a page from your book, So its drawn at full size in cad and then I simply scale down to create an STL file. ergo does not need to be only confided to 4mm. 3, 4 S and O gauge are also doable.
I am picking I have the same PDF drawing's James has referenced.

What I found interesting is the number perpetuation's you can create even to a so called std design. EG 2 door, 3 door, four door or 5 door. Two different types of side doors, two very different types of knee washer plates. There are a few permutations in the underframe furniture as well. Add in a few different builders plates and railway registration plates and you get quite a number of permeations spinning out of just one std drawing.
PS I hope Lazarus is the winner
cheers
Phil,

 

[Phil G]

Hi Phil,

This is how I print them, a 0.8mm plywood panel with the engraved planking drops in from the top and fixes to the solebars which protrude into the space a little.
View attachment 10602

As for 1923 RCH brake lever guards (thank you for the correct term), I could have a look at them. I have the drawings. I'll add it to my long to-do list.

Thats very interesting, I have gone for a fully accurate underframe for the floor to rest on. The buffer side the spring wire hole nicely fits into the buffer trimmer assy, and on the other side just to the the wheel side of the cross tie rod. Which is why I am having to print it the other way round and at an angle of 30 degrees, I have also gone with a separate resin printed floor, partly as that opens up the bottom doors, or no bottom doors option.
Just one other question, have you gone for full hex nut heads on the outside of wagon plates? I have seen a few wagon photos where these seem to have been replaced with square nuts.
cheers
phil.

 

[Hayfield]

Hmm.

1. I have two resin printers.

2. if I build 47S I will need some wagons.

The snag is that all my time is taken up with Templot. At present there's a battle going on between Lazarus and EMF, and it's not clear which is winning.

Martin.

Martin

I am happy to donate the odd loco and a couple of wagons,

John

 

[James Walters]

Thats very interesting, I have gone for a fully accurate underframe for the floor to rest on. The buffer side the spring wire hole nicely fits into the buffer trimmer assy, and on the other side just to the the wheel side of the cross tie rod. Which is why I am having to print it the other way round and at an angle of 30 degrees, I have also gone with a separate resin printed floor, partly as that opens up the bottom doors, or no bottom doors option.
Just one other question, have you gone for full hex nut heads on the outside of wagon plates? I have seen a few wagon photos where these seem to have been replaced with square nuts.
cheers
phil.

I have tried printing these 'accurately' before. The timber underframe was good, it was one of my first 3d prints. It even had proper sprung axle boxes. This was before I'd discovered the guitar wire variety of springing. But the steel underframes are (I think) pretty much impossible to print to accurate dimensions. Unless of course one beef's-up the steel sections, at which point the fidelity is lost. For an 'accurate' wagon I think that etched brass is the better medium.
My own Midland wagons are printed to be usable layout wagons. They look good, work well and I can print 12 at a time with a 100% success rate.
My SE&CR hopper wagon which you might have seen are printed the other way up at an angle.

I found that resin printed floors tended to curl, which is why I went with plywood. I'm working on some tiny brass strap hinges with which I hope to make a few wagons with opening bottom doors for the Jubilee Layout. If it works out I'll share how it works here.

Regarding the wagon plates. My understanding is that the (number) plates had square holes to take the square shank of a carriage bolt, so I modelled a dome head, builders plates had round holes for screws - but I'm happy to hear otherwise.
However, I'm going to remove the plates from my .stl file as I plan to etch a batch using the fibre laser, and set the variable function to engrave consecutive numbers from various lots. Not that the numbers or the bolt head styles can be seen from a normal viewing distance anyway. But they do look good, especially in 7mm scale.

I think this was the closest I got to a steel underframe which would print reliably, note I ditched the accuracy of the webs etc on the inner parts. I can't quite remember now what I was thinking re buffer and coupling springing as it was a few years ago when I was playing with these, but it explains the curious holes on the outer edges of the centre frames. I'll have to dig into the archive a little further to ascertain my thinking at the time.. Those that I made had etched brass axleguards, for which I probably still have the artwork.
You'll see I only modelled a 1/4 frame which I mirrored (twice) to create the whole. It's quite a time-saver.

 

[Phil G]

But the steel underframes are (I think) pretty much impossible to print to accurate dimensions. Unless of course one beef's-up the steel sections, at which point the fidelity is lost.

Hi James,
yes I agree with you, an accurately dimensioned metal underframe will not work on a resin printer. its simply to thin and flimsy.
.
re the wagon plates, thats a lot of good info you have provide there. Can you really get all the detail of a wagon builder plate laser cut with this fiber laser?
It was only when reading your replay I realized I have inadvertently used the word plate when what I mean to write was wagon plank.
IE I was talking about the visible 1/2 and 5/8 whit nuts on the outside of the planks. Most are hex heads but on some photos you can clearly see they have used square nuts.
On the inside they would have either been coach bolts, if no inner washer tie plates were used or std bolts if washer plates were used,
cheers
Phil

 

[Michael Woods]

Hi James - there may be a separate thread but are you fitting wire compensation springs to your axles?

 

[Michael Woods]

Hi Phil,

This is how I print them, a 0.8mm plywood panel with the engraved planking drops in from the top and fixes to the solebars which protrude into the space a little.
View attachment 10602

As for 1923 RCH brake lever guards (thank you for the correct term), I could have a look at them. I have the drawings. I'll add it to my long to-do list.

sorry James I was referring to this model.

 

[James Walters]

Hi Michael,

Yes, guitar string springs in 3d printed bearing carriers. They work well.

James

 

[Phil G]

Hi James,
what weight are the wagons? And most importantly what is the thickness or note of the string your using?
cheers
Phil,

 

[Martin Wynne]

@James Walters

James has posted a video on using the fibre laser. Looks good, apart from the price!

Martin.

 

[James Walters]

Indeed, the price is prohibitive. I couldn't afford one.

It does make nice things though...

 

[James Walters]

Hi James,
what weight are the wagons? And most importantly what is the thickness or note of the string your using?
cheers
Phil,

Hi Phil,
I'm adding 32g of lead in the form of a white metal casting under the floor to bring the total weight to 50g. Not sure of the wire gauge, I'll have to measure one. There in my studio at the moment so that will have to wait until I'm next there.

 

[Phil G]

Indeed, the price is prohibitive. I couldn't afford one.

It does make nice things though...

View attachment 10778

is that a seek preview of your next video project
also did you say you had to give it back at some point on the video?

 

[Phil G]

Hi Guys,
Just out of interest, mainly because it is sometimes hard to gauge all thinks UK for as far away as NZ. Would I be right in saying both the number of etched brass/ nickel silver Items related to railway modeling is on the wain? As are the number of places such etching can be done? A good example would be the old Bill Bedford etched W irons for example.

Mainly asking because whilst its hard to see a fiber laser ever replacing etching as a mass production process. I could see ( for all the people very very deep pockets) getting one for say prototyping purposes. It could be very useful tool to get a project 100% right before going out to source a more mass production friendly process.
cheers
Phil,

 

[James Walters]

is that a seek preview of your next video project
also did you say you had to give it back at some point on the video?

It's not what I had in mind for the next video. This is a little side project which seems to have crept in.

 

[Rob Manchester]

Hi James,
Looks like a nice machine ( at a price ). All we need now is some CAD drawings for out of production etched kits and we can be producing our own kits in no time.....

If the max cut depth in nickel silver or brass is around 0.5mm does that mean that by using multiple passes to avoid distortion as in the video you could repeat these shallow 'cuts' to cut out thicker material ?

There are not many companies who will do short run etching these days. A lot of them used to specialise in items for the jewellery market but like many trades that is mainly done abroad now.

Rob

 

[James Walters]

Hi Rob,

Exactly, with lots of passes, thicker materials can be cut. I've managed 2mm stainless and brass so far, but it is very slow going. On the plus side one can get on with something else whilst the machine buzzes away, although I wouldn't want to leave the machine unattended completely.
As an aside, are your the Rob who said hello, just as I was leaving Scalefour North? The internet is a wonderful thing, but it does make it difficult sometimes to put names to faces. I hope it is you as I enjoyed our very brief exchange at Crewe, if you make it to Scaleforum do please stop by for a more fulsome chat, I think we share similar interests on the model engineering front.
Also are you the same Rob of Arlington Colliery? If so, I doff my cap to your model making artistry - I really enjoy your posts on the S4 forum.
If you'd like anything 'etched' drop me a line, I feel quite lucky to get to play with things which would otherwise be beyond my means and I enjoy sharing the utility of the machines where I can.

Cheers,
James