big Problems with Candy/Hoover in Germany

[3beltwesty]

RE; So . . . what is screwed, and what is welded drum?

The part that rotates that holds ones clothes is often called the "basket" or "washing machine basket" in Engineering lingo.

To start with the 201 series Stainless Steel strip is just a polished thin sheet off a giant roll.

It is cut/punched out in a long rectangle, the long side is the circumference of the basket. It is rolled/bent into its tube shape and either screwed, crimped, welded together or a combo of several methods.

As the spin/extract speed gets higher in newer designs, the "joint/seam" becomes more stressed. Thus a crappy poor joint maybe fine with an ancient 500 rpm extract, but dicey at 1200 rpm. The stress goes up as the square of the rpm. A basket at 1500 rpm has 9 times the stress on the "joint/seam" as one at 500 rpm.

It is made like a "soup" can; that some have a "seam/joint"

This joint is what failed.

 

[solsburian]

Just for a comparison, here is the drum seam from my parents Hotpoint WF541 that has the recently phased out Hotpoint drum:

 

[solsburian]

... and here is a pic of our Hoover's drum seam that will have the same kind of seam on the Hoover/Candy machines that exploded. I checked today and the Indesit drum now fitted to Hotpoints also has this kind of seam:

 

[nrones]

Don"t see any price change tbh..

As far as I can see, the WT541"s drum is screwed, and Hoover is the welded?(aswell as the new indesits?)
But it doesn"t seem that screwing is more expencive than welding? Is there sth I misunderstood?

thanks 4 such a proffesional reply! and Happy new year!!

 

[3beltwesty]

Welds

Using a few screws would probably be cheaper than welding is my guess. Since 201 stainless is quite "springy" aligning the holes could be not easy. With a decent weld there is one long strong joint. Welding is used with piping, custom stainless ducts in many industries.

In a consumer product, production cost is a massive concern. Thus one might have a crimped joint and just a few tack welds or few screws. In design reviews, wringing out (reducing ) costs matter. Designs are changed to save a few cents. ( 1/100 of a dollar ). If 1 million units are made, saving 5 cents is 50000 dollars. There are folks whose job is to just lower the cost.

As the rpm increases, the design has to be better to have this joint not fail.