Laser versus Waterjet Cutting

[duste]

Decided to start a new thread instead of clogging the other thread with my shit.

Originally decided on having my engine mount profiles waterjet cut, however a snap decision late last night saw me also send out a bunch of requests for quotes from laser cutting companies.

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-snc7/578211_10200462391703151_1382907070_n.jpg

Anyone have any experience with either or? Which would be best for 8mm mild steel?

Quotes are much the same at the moment, laser-cutting being a little bit cheaper...
Waterjet cutting from one company: $400 inc. GST and supply of materials, no bevels
Laser cutting from another company: $360 exc. GST for cutting and supply of materials, and ~$78 exc. GST for beveling the necessary edges. (~$480 total inc. GST)

Would be very handy to have the edges beveled at the same time, particularly with the laser-cutting, as I presume it would harden the edges - would certainly save me a lot of time and frustration.

Thanks.

[Lump]

I did wonder why you were talking water jet cutting, I would go the laser cutting method and just bevel the edges myself with a file. Shouldnt need much anyway
8mm PL is not a problem
are these temp mounts? Going to be quite heavy for what they are

[duste]

Yeah they're only temporary mounts - they've been designed such that I can mount the engine and move it around while I'm trying to line up everything (diff, steering rack, etc).

Once it's all done I'll mark out the appropriate angles and design permanent mounts.

Will wait for a few more quotes but it looks like laser-cutting and DIY beveling is the sensible option.

[mod]

Laser Cutting all the way from 0.5mm to 20mm thick (I use RCR Laser as I work for RCR Mining)

I only ever use Jetcut if you were to cut thick Aluminium(>8mm) or stainless plates(>12m)

Bevel on 8mm plates just use a grinder, not worth putting one on via machine unless its at least 12mm or thicker

[-Luke-]

I only ever use Jetcut if you were to cut thick Aluminium(>8mm) or stainless plates(>12m)

Legit question: why?

[duste]

I was always under the impression that laser-cutting would deform thin sheet? Purely an assumption; I've never done this sort of thing before.

Thanks for the info btw. Pending stress analysis the final mounts will be made out of ally, but hopefully not more than 8mm thick!

[vbroom]

Laser will give you a cleaner cut.

Water jet will give you a sandblasted finish to the edges so you'll have to machine/polish them back if you want a smooth ali finish

If they're only temp mounts....might as well go the cheaper option?

I've had jet stuff done through Intracut in Bayswater. They can also bevel edges with water jet.

Also, laser will not deform thin sheet. You could even cut paper thin ali if you wanted to without deforming it.

It come down to the size, power and speed of the beam. Which are all adjustable.

[200MPH]

Action laser cutting in Bayswater have done heaps of work for me and a few mates. Steel and ali. They get a sister water jet company to do thicker ali stuff.

Recommend.

[duste]

Just received a quote back from Josh @ Action Laser Cutting...$88, inc. GST and supply of materials.

What a price difference! Not only between waterjet cutting, but also with the other quote I received for laser-cutting...

[cplagz]

Yeah Action are great to deal with. I had a flange cut off a gasket I sent them for a similar price.

[R3N]

Used Action a while back to make up a tow hook... made it up with shit photoshop drawing i gave them

[mod]

Legit question: why?

Something to do with the reflectivity of ali and stainless and also carbon content also the power rating off the laser need more Kw etc.. google it lol
Its been a while since I worked in a profile cutting company

Yes in Europe there are companies that can cut up to 50mm thick with lasers but not here in WA
I think Sandvik can cut up to 25mm Stainless on their Laser IIRC

[duste]

My partner picked these up today after work for me... I'll keep my comments and photos to myself until I receive a possible explanation from Action Laser Cutting for the quality (or lack thereof).

[Lump]

post the pics up dude, we might be able to help

[Azrian]

Pics

[duste]

Suppose I was going to post it regardless:

http://duste.net/img/190e_ls1/engine-mounts_laser-cutting_120212_lo.png (http://duste.net/img/190e_ls1/engine-mounts_laser-cutting_120212.png)

Clicky for hi-res.

You can clearly see where they've started the laser-cut right on the edge of the profiles - surely it would be most logical to start slightly offset and come in for a clean cut? This and the non-square edges annoys me the most, and it mostly occurs on the edges which would have been used for aligning the components for welding.

You can also see gouges to the surface, though this is purely cosmetic and doesn't affect the ability to align components.

[Lump]

looks ok to me.
maybe you should of allowed for machining if what you want is so critical?

[duste]

Did you look at the hi-res? Lol.

Looks shit to me, but this is my first experience with laser-cutting - surely that's not the norm, else I may as well have had someone plasma cut it by hand.

[Lump]

yes i did, but then again i have had turbo flanges cut before so i know what they can be like.
anyway, just my opinion, good luck with it

[Evman]

I know where you're coming from duste. Really they should be 100% perfect. It's a major reason for getting it done with a machine like that

[Lump]

everything works to a tolerance, what tolerance did you/they specify Duste?

[Alt_F4]

everything works to a tolerance, what tolerance did you/they specify Duste?
LOL the drafty in me likes where this thread is going

[duste]

everything works to a tolerance, what tolerance did you/they specify Duste?

Apparently +/-2mm according to the holes burned on the edge of the profiles. :)

As I said, I'm awaiting an explanation from Action as to why the profiles turned out how they did. A tolerance of five football fields may very well be the answer.

[Lump]

haha, i guess you got burned then

[mod]

Those are pretty bad coming from a Laser machine...

Laser are +/-0.2mm
Oxy,Plasma & Jetcut are +/-2mm

[duste]

Received a reply from Action:


Good morning Hayden,

I am sorry to hear you are unhappy with our service,

We can definitely replace the scratched parts for you.

The lead-ins are normally a lot better than this, but unfortunately they are unavoidable, the best we can do for this is put the lead-in an alternative place that is in a more convenient place for your application.

From the picture, the cuts them self look pretty good,

If you could indicate the parts that toy require recutting, I can get the ball rolling.

Sorry for any inconvenience this may have caused


Kind regards,

[cplagz]

They supplied the material correct? It will just be offcuts of shit they have lying around hence the surface gouging. As for where the laser started the cut, that's unacceptable IMHO, especially seeing as you need the face flat to be able to weld it.

[Azrian]

those faces look flat enough to weld. Weld fills all the gaps. Also why have you used such thick plate? With that thickness i would be using full pen butt welds so they would require bevelling anyway.

[mod]

Are those mild steel or Aluminium?

Full pen on those plates would be overkill for what he's doing? A 6mm fillets should be fine I'd say.

[cplagz]

those faces look flat enough to weld. Weld fills all the gaps. Also why have you used such thick plate? With that thickness i would be using full pen butt welds so they would require bevelling anyway.

I think the problem is there is a protruding edge, not a bevel/missing edge. So it wont fit flush on the other plate, it's like the laser stopped there and it's slag build up per-se

[duste]

They supplied the material correct? It will just be offcuts of shit they have lying around hence the surface gouging. As for where the laser started the cut, that's unacceptable IMHO, especially seeing as you need the face flat to be able to weld it.

Correct. Not fussed about the gouging as it is purely cosmetic.

My concern was fore-mostly with the laser entry/exit defects.



those faces look flat enough to weld. Weld fills all the gaps. Also why have you used such thick plate? With that thickness i would be using full pen butt welds so they would require bevelling anyway.


Are those mild steel or Aluminium?

Full pen on those plates would be overkill for what he's doing? A 6mm fillets should be fine I'd say.


I think the problem is there is a protruding edge, not a bevel/missing edge. So it wont fit flush on the other plate, it's like the laser stopped there and it's slag build up per-se

Mild steel. The plan is to add a 5-6mm chamfer to the edges, align them flat and weld away. Apologies on the paint-spec drawing, but no CAD for me here at work:
http://i.imgur.com/Fzmdgh6.png

Unfortunately it is these edges that have the defects, though some may be salvageable as a result of the chamfering taking away the defect.

As these are only temporary mounts, I opted for overkill. These will determine the final geometry, and the final mounts will be optimised and FEA'd to prove "it's safe" and can handle the torque output, both in its current state and future configurations.

[upgarage]

no offence
but it sounds like you dont know what you are doing

[duste]

None taken, first time I've done something of the sort, so to some extent you may be correct. Funnily enough, I'd have not made a thread in the first place if I did know what I was doing.

Feel free to throw in your wisdom if you've any to offer.

[180SXTCY]

Fuck Hayden your making engine mounts not NASA spec high tolerance precision engineering and they're only your proto type arnt they?

[duste]

Of course they're only a prototype, I'd be much more annoyed if they were to be the real deal. :p

Fact is, all I asked Action was whether this was the norm, as I was concerned of how the final mounts would turn out if I went with laser-cutting again. It's not as if I went demanding replacement profile cuts - it was offered as this was an error at their end, to which I told them I didn't expect everything to be replaced, just the worst.

There's only four profiles that need to be re-cut anyway, and that's due to a mix of defects, including laser entry/exit "wounds", non-square edges, and under-sizing. The rest of them, as I mentioned might be the case before, can be cleaned up when I chamfer the edges so no biggy on that front.

Action have been very helpful in rectifying the problems, so I'll still be using them in future.

[Azrian]

This is mounts we made for a LS1 on a Range Rover.
http://i520.photobucket.com/albums/w326/ross12631942/IMG_0090.jpg
http://i520.photobucket.com/albums/w326/ross12631942/IMG_0091.jpg
http://i520.photobucket.com/albums/w326/ross12631942/IMG_0094.jpg
http://i520.photobucket.com/albums/w326/ross12631942/IMG_0105.jpg


The engine was hanging in the engine bay, we cut cardboard templates, cut some scrap steel we had and welded in place in the engine bay. There will be more movement and adjustment in the rubber mounts then the adjustments you will make in your mounts. Also these mounts will cop way more punishment offroad then a road car mounts will see.

[duste]

The engine was hanging in the engine bay, we cut cardboard templates, cut some scrap steel we had and welded in place in the engine bay. There will be more movement and adjustment in the rubber mounts then the adjustments you will make in your mounts. Also these mounts will cop way more punishment offroad then a road car mounts will see.

That is what Josh intended to do, but given he's busy as fuck with everyone else wanting their cars done for RaceWars I've opted to go back to these temporary mounts.

As I don't have a welder (nor do I know how to weld) my best bet is being able to move the engine around with adjustable mounts, lock them in position, remove and take measurements, design more appropriate mounts then have someone else weld them off-site.

With your mounts, the "chassis mount" (where it bolts to the chassis/original rubber mount) is quite central between your "engine mount" (where it bolts to the engine). With mine, however, the chassis mount is right back at the rear-most bolts, and quite possibly further back:

http://i.imgur.com/TN29NFF.png

Could always go the overkill route, but that's no fun; I'd much rather FEA it and learn from it.