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Medium volume production techniques for high quality machine enclosures

Luke Rickert

Hot Rolled
Joined
Oct 24, 2007
Location
OSLO
Hi everyone I am currently working for a company that makes small coffee roasters and we need a good way to create enclosures (not super complicated but not quite just a rectangular box, there are doors, openings, sloped sides etc.) These need to be able to be nicely finished and go in a high end coffee shop as well as for production environments. The size is around 500mm in all directions (about 20 inches) so not tiny but not huge. We need more or less easy access to the inside for easy service etc. There is a door on the front of the machine that is particularly problematic.

The challenge is that we are building on the order of 100-500 machines per year so it isn't enough to justify complicated sheet metal pressings or die cast aluminum/zinc which would otherwise seem to me like good options.

Right now we have a combination of a frame made from bent and welded sheet (mostly stainless), some milled aluminum panels and thin stainless sheets (laser cut) but it really doesn't work that well and lacks the feel and apparent quality a 20k USD coffee roaster should have.

I am trying to find that elusive middle way, something that is going to require some amount of tooling cost but not deep drawn pressing tool type prices. Right now the parts are coming from China which isn't ideal for many reasons (and definently isn't my choice) My preference is something we can have made in Europe or the US (we are in Norway so everything is an import anyway)

So far I am thinking perhaps we have custom aluminum extrusions made that will work with some sort of stiffened panels (metal sandwich) although I haven't modeled that up yet so I am not sure if it would look ok or not.

Another option I am considering is Shell Casting as it is automated and less expensive than die casting. I can envision an enclosure made up of separate panels (in aluminum) that are attached together with fasteners (with machined interfaces)


Does anyone have any ideas? My background is more mechanical engineering than manufacturing and while I have a good bit of experience with hands on machining, fabricating parts of this sort for production is a bit out of my area of expertise.

thanks

Luke
 

Scruffy887

Titanium
Joined
Dec 17, 2012
Location
Se Ma USA
In the USA a Chinese 1kw fiber laser with 1.5 x 1.5 meter cutting area is maybe US $100k. Easily and quickly cut up to 10 gauge with Nitrogen leaving a clean shiny edge. A full CNC press brake with European tooling is another 100k. Bodor for the laser, Trumpf for the press brake.
Once you get the possibilities of formed sheet metal in your head you will find a lot more design ideas for your product. A fiber laser can cut with a .1mm kerf with no visible discoloration on top and the same on the bottom almost. It can cut a small slot in a sheet to accept a small tab on another sheet for exact location. A series of slots that are the width of the sheet metal used locate another formed part. The tabs can even be hook shaped so once inserted the part gets pushed to hook the parts together. The hook opening can be tight enough that you need a rubber mallet to lock them together, or just loose enough if the parts need to be taken apart for service.
 

Luke Rickert

Hot Rolled
Joined
Oct 24, 2007
Location
OSLO
I definently see the advantages of brining production in house, it may be that is the only way to get the quality we are looking for but it will probably take a while for the management to figure that out :) Ideally we can find a supplier over the border in Sweden or elsewhere in Europe who can do the work for a reasonable cost and with appropriate quality.

The question is what type of fabrication is the best option, sheet metal might be the answer but I am not sure at this scale. If it was up to me I would do the whole thing in iron castings, the weight doesn't really matter as you need a crane or fork truck to move it safely as is.

Luke
 

memphisjed

Stainless
Joined
Jan 21, 2019
Location
Memphis
Design it and have the process follow if you are not fluent in a design. Zahner did the Starbucks in Chicago that makes you feel like you are in a roaster with rolls (they punched the material, rolled by others).
Aluminum looks cheap in cooking products- minus cast like the mr peanut roasters or Japanese tea pots.

Bronze and, smooth stainless, and glass all look good most of the time. Also they don’t taste bad with coffee.

Asking about how without a few designs concepts is cart with no wheels in front of horse.

Btw, it should be all key seamed copper with forged iron hardware, iconel rivets attaching the two. See, saved you thousands in equipment cost.
 

barbter

Diamond
Joined
Oct 27, 2007
Location
On Tour...
Id be looking at making a nice beefy (sturdy) front panel - then making that the chassis where everything else can be screwed to it and hang from it.
Say 3" thick billet and shape/gut as required leaving raised tapped bosses facing backwards, and machine locations/tapped holes in the sides to screw the side panels to - whether they are machined or laser cut or 1x piece bent "U" etc depends on what you have to attach in there.
That should give you the "expensive feel" and you could even engrave the front saying "Aerospace Aluminium" :D
 

jaguar36

Cast Iron
Joined
May 13, 2015
Location
SE, PA
Right now we have a combination of a frame made from bent and welded sheet (mostly stainless), some milled aluminum panels and thin stainless sheets (laser cut) but it really doesn't work that well and lacks the feel and apparent quality a 20k USD coffee roaster should have.

If you already have a design that looks good, but just doesn't feel nice, just increase the thickness of the panels. You'll make the whole thing more rigid, it will feel nicer and hold together better, and won't mean a full redesign.
 

Strostkovy

Stainless
Joined
Oct 29, 2017
Sheet metal doors need double bends, and sometimes an additional hem, on all sides to feel right. I tend to make double sided doors for rigidity, which can be easier.
 

Luke Rickert

Hot Rolled
Joined
Oct 24, 2007
Location
OSLO
Sheet metal doors need double bends, and sometimes an additional hem, on all sides to feel right. I tend to make double sided doors for rigidity, which can be easier.


Thanks Strostkovy, I have been thinking along these lines. I will try to come up with a double sided door design although that isn't simple given the existing profile which has a curved transition top and bottom.

Luke
 

Pattnmaker

Stainless
Joined
Nov 2, 2007
Location
Hamilton, Ontario
What about sand cast? Really flexible in terms of shapes including decorative elements. Can be sand or shot blasted with certain elements polished for a really high quality look.
 

boslab

Titanium
Joined
Jan 6, 2007
Location
wales.uk
Unfortunately the presentation of your product depend on doing it really well, it would be nice to cobble somthing together from sheet extrusions and a bit of tig but overall, it is going to look cheap so I’d say you may well have to employ the services of an industrial designer to get the finish and aesthetic you need, the brief so far is what can be cobbled together, not a good philosophy imho, what people see is what sells the things, it shouldn’t be an afterthought it’s as important as the pressure vessel, surface finish or functionality, are you looking for modern contemporary ,retro , Art Deco
Look at a pacemaker lathe compared to a dsg one, the old pacemakers Art Deco or Nuevo whichever is down right beautiful ( not just my opinion) thoughts
Local university with industrial design course, they should jump at the chance to come up with somthing, usually for free just to get the departments name acknowledgment have a think and add a photo we’re all happy to contribute but I know there are good designs and mediocre ( what I’d probably create!)
Just thinking out loud ( I do like the copper and rivets look myself, the mrs likes easy clean but hates stainless as most women home in on scratches, they can’t help it I reckon) brushed stainless shows them off so well, slightest mark sticks out,
Mark
 








 
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