What's the purpose of this weld?

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6/12/2018 4:06 PM

Sorry, I'm ignorant on this. It's a pic of the new Kawasaki. What is the purpose of this weld I've circled? Why couldn't it just be one piece. Appreciate any info. Just curious...

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6/12/2018 4:07 PM

To connect the square tubing to the machined piece that bolts to the frame.

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6/12/2018 4:08 PM

looks like they joined square stock to a milled piece. that's my guess.

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6/12/2018 4:08 PM

It’s a machined bracket welded to the tube. They couldn’t machine that whole spar and bracket.

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Washed up moto and enduro weekend warrior.

6/12/2018 4:10 PM

Why not mill a single piece or cast a single piece? What is the benefit of a standard piece welded to a milled piece? Seems like extra work for really no reason? I'm sure I'm wrong. Just want to know why.

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6/12/2018 4:13 PM

Probably need the square tubing for flex/strength characteristics but had to machine that piece for the exhaust to fit between it and the shock spring.

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6/12/2018 4:22 PM

You can tell the weld holds it together because of the way it is

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6/12/2018 4:22 PM

TXDirt wrote:

Why not mill a single piece or cast a single piece? What is the benefit of a standard piece welded to a milled piece? Seems ...more

Because It would probably cost $100 to manufacture that entire assembly as one piece, instead of 69 cents to do it the way they did. There are probably similar compromises all over the motorcycle.
My numbers may be way off, but I can almost guarantee you they did it so your KXF450 doesn't cost $20,000.

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Braaapin' aint easy.

6/12/2018 4:23 PM

I have a theory. If you look at this picture you don't see the weld/cast part. The side panel covers that perfectly. Certainly it looks more "advanced" or "high-tech" or "factory" to see that machined piece only.

Do you think this could be done for marketing purposes only? From the appearance you would think the entire piece is machined, when it's not.

If it serves some technical purpose, why is it coincidental that the side panel covers the exact place of the weld.

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6/12/2018 4:29 PM
Edited Date/Time: 6/12/2018 4:39 PM

it's the cheapest, easiest way. machining brackets and bending tubing is much less complicated than casting or forging... and machining the entire subframe would just be too time consuming and wasteful (i.e. expensive). Imagine the size of billet you'd need to make a subframe. You'd be removing 98% of the material. that's not very efficient. ...and top of all that, tubing is the ultimate building material. It offers many advantages over other types of frame and chassis construction when it comes to time and money.

casting and forging are investments in specific tools. general bending and small finish machine work requires very little investment, and is almost entirely reconfigurable and standardized.

it's not rocket science or marketing. It's just basic manufacturing logic and completely inline with Japanese manufacturing philosophy. It's know as the Kaizen philosophy, popularized by Toyota.

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6/12/2018 4:33 PM
Edited Date/Time: 6/12/2018 4:36 PM

TXDirt wrote:

I have a theory. If you look at this picture you don't see the weld/cast part. The side panel covers that perfectly. Certainly ...more

The reason the way it is is because tube is stronger than plate when its long. If you were to grab the fender and pull it to the side like you were trying to bend the subframe, you would bend it easier if it were made of plate. Why not make the plate thicker to make it stronger? Weight. ALSO, fastening with a plate is different strength wise too. Theres less material in that tube for a bolt than in the plate. Also the bolt wont pinch the plate.

Hope this answers your question.

Edit: also you can waterjet cut a billion of those plates in no time. Cutting and bending tube is a breeze. Faster and easier mfg methods are considered, as someone else mentioned

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6/12/2018 4:42 PM

TXDirt wrote:

Why not mill a single piece or cast a single piece? What is the benefit of a standard piece welded to a milled piece? Seems ...more

Falcon wrote:

Because It would probably cost $100 to manufacture that entire assembly as one piece, instead of 69 cents to do it the way ...more

Exactly! that's all there is to it. ..and imho, it's better for it.

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6/12/2018 4:44 PM

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6/12/2018 4:49 PM

TXDirt wrote:

I have a theory. If you look at this picture you don't see the weld/cast part. The side panel covers that perfectly. Certainly ...more

Absolutely not. It was just a logical place to stop the side plate.

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6/12/2018 4:58 PM

Lighter, faster, stronger, cheaper:

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6/12/2018 5:00 PM

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6/12/2018 5:02 PM

Jeremy Macbeth wrote:

Lighter, faster, stronger, cheaper:

Photo

Are those the sub frames that break when you seat bounce? Definitely stronger.

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6/12/2018 5:31 PM

Jeremy Macbeth wrote:

Lighter, faster, stronger, cheaper:

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maybe cheaper to make part, but id have to guess the mold was not cheap to make..

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6/12/2018 5:34 PM

kb228 wrote:

You can tell the weld holds it together because of the way it is

That’s pretty neat!

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6/12/2018 5:40 PM

Jeremy Macbeth wrote:

Lighter, faster, stronger, cheaper:

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Not sure anyone who has broken and replaced one would agree with you lol

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6/12/2018 5:46 PM

kb228 wrote:

You can tell the weld holds it together because of the way it is

America is great because America is good.

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6/12/2018 5:50 PM

because the extruded box tubing is light, very strong in flexural strength (i.e. "up and down", as in seat bouncing, etc.), but terrible in compression w/o a solid insert. Since the bolt going through the end attaching it to the main frame has to be in compression through the subframe (and the bolt is in shear during normal riding loads), they address both stress modes while keeping costs low by using this hybrid approach.

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6/12/2018 5:52 PM

A solid piece to a hollow piece!

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6/12/2018 5:57 PM

To hold those two pieces of aluminum together.

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Take it to the limit, one more time!

6/12/2018 6:22 PM

boot might catch on it if it was not covered

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6/12/2018 6:25 PM

One is hollow, the other is a solid machined piece.
Making it one solid piece would be heavy, costly and time consuming. The flex characteristics would also be considerably different.

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"Nothing happens until something moves"

6/12/2018 6:28 PM

TXDirt wrote:

I have a theory. If you look at this picture you don't see the weld/cast part. The side panel covers that perfectly. Certainly ...more

Here I circled all the other welds they forgot to cover up with plastic, per your theory. Photo

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Mantis Toboggan, M.D

6/12/2018 6:50 PM

Simple really...to highlight the awesome welding skills of the dude at position 12 on the assembly line. Remove cap, spooge weld in place, send assy to next position.....repeat.

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If it ain't yer's don't take it, If it ain't the truth dont say it, If it ain't right don't do it...Marcus Aurelius

6/12/2018 7:11 PM

plowboy wrote:

Simple really...to highlight the awesome welding skills of the dude at position 12 on the assembly line. Remove cap, spooge ...more

Robot welded for sure.

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6/12/2018 7:14 PM

Here’s a works version of that bike, so obviously nothing to do with cutting cost at the sake of performance...
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"Nothing happens until something moves"