Engineering: how NOT to do it

[ArMaP]

The chains on the right have slipped over the sprocket, and the sensors for registering the height of the lift (on both the left AND right) were confused, so it stopped.

Well, at least in this case the machine was smarter than the "expert".

[PLAYSWITHMACHINES]

That's right, it was well designed. It will stop rather than crash, unlike the expensive robot
The computer knew what was wrong, the humans didn't...

A bit of extra software could have displayed a message, for example, and then they would know where to look

[The Matrix Traveller]

Re my earlier post there is a couple of building companies investing in Interlocking Systems
to some degree. This includes Commercial properties as well.
Esp. after the Earthquake we had in Christchurch a couple of years ago.

One such Co. is LockWood.

Most of the construction of buildings involves Interlocking Components.

They do however use some tie rods in some cases .

Here is an example of their wall structures.


(sorry picture is gone, but here is the Homepage---PWM)The tie rod seen in the above anchors the wall to the floor if a concrete pad is used
rather than a wooden floor.

In areas subject to high winds these tie rods are sometimes used with wooden floor constructions.

The silver wall is a aluminium clad exterior wall, where aluminium sheet is integrated with
an exterior wooden wall.

In other words the exterior wall planks are produced with the aluminium sheet attached.

But as you can see it is pretty much a "Interlocking Structure".

I am sure you will see more of this Tech. in the future.

Another Co. is Modulock.

No doubt there are others as well.

[PLAYSWITHMACHINES]

Good point Matrix.
This also means faster more secure constuction. No more nails & bolts etc
Kind of like Ikea furniture

Are you ready for part 4?

[PLAYSWITHMACHINES]

Now this machine is very large.
It's part of a transport system for large pipes.
The problem wass, the man who ordered it had no idea what he was doing, and the general construction company that built it had no idea what they were doing, either!

It was (according to the builders) specified to lift pipes weighing 80Kg.
The problem was, that was the lightest pipe in production, the heaviest was 280Kg!
Apart from that small blunder, it turned out that the damn thing couldn't even lift it's own weight!
The main moving part weighed over 4 tons!
In this picture, you can see the moving part is rubbing against the frame, not even so much as a washer between them:



Needless to say, the (too small) axles & bearings gave up within a month, this axle would have broken clean off, given time;



After countless repairs & retrofits, the machine was dumped the following year...
Cost? About 460,000 Euro's.......



Elsewhere in this factory, another machine had broken down
This time, a lube pipe has broken off a year or 2 earlier;



The cage has rusted away & the rollers spilled out of the bearing.
And i had to SHOW them why the machine had stopped!
This could have been fixed for about 100 bucks, but no-one bothered.



Elsewhere in that same factory, a sludge removal conveyor has jammed.......



This is part of the filter for a gigantic industrial sanding machine.
What has happened is the operators just threw the bits of broken belts into the machine, rather than removing & disposing of them.
These bits have wrapped around the axle, broken the chain & some metal strips inside the machine.
Total repair time: 4 hours



On to another factory, this time it's to dismantle an extrusion press:



The problem is that a crack has developed in the main hydraulic cylinder, which is 4 feet diameter, and 10 feet long.
The crack happened here between the cylinder & the tie-rod hole:



Why?
Because the holes were too damn close to the cylinder, they weakened it!
Design fault

After several very costly repairs, they threw it out....
Duuuuuuuuuuuuuuuuhhhh!



Next was a very interesting, yet insane job i had to do

This was to install an infra-red camera on top of an oven, that could check for broken pins on the transport chain. This chain is about a mile long, so if it even LOOKS like it's going to break, the whole machine has to stop at once.
You don't want to unwrap half a mile of chain from all those (very hot) sprockets!

For some reason, they wanted a 'heat shield' behind the chain.I pointed out that the Infra-red heat coming from the oven would be an excellent backround source for the camera, which was only going to film a profile.
A diffuse backround source, such as that from the oven itself, was ideal.



To everybody's amazement (except mine LOL) the camera didn't film a thing...

So they then decided (and this is the honest truth, i swear) to buy a special diffuse IR light source, and stick it on the heat shield!!
I duly did as they told me;


Stoopid, or what?


OK last but not least, i was asked to fit a label printer into a filing cabinet in such a way as it could still be used, without having to open up the cabinet.
It took me almost a day, even then we had to extend the monitor cable (yes the PC is in there as well) otherwise it would fall off the cabinet when you opened a drawer to change the ribbon etc.



Mind you, it DOES look cool, but was probably the stupidest job i ever had to do

There's more in the archives.....
PWM

[ArMaP]

Kind of like Ikea furniture

I don't know if that's a good idea.

Here in Portugal we use mostly concrete and bricks.

[ArMaP]

I think you should write your repair-related memories, it has the potential to be a best-seller.

[1Worldwatcher]

I think the Extractor was the biggest 'Whoops!" of them all, it would have been quite easy with regular maintenance checks to see this was going too give way. I hope that the company that had designed the machinery divvied up the offset of design flaws back to the company that had purchased, it. I can think of a few ways of how they tried to mend the situation, but still scary to think of how much force was being applied to the machines mechanical parts while this machine was in use.

The Sledge separator also seems too be a maintenance issue from photos supplied PWM, I personally think that "YOU" PWM need too design a 'Maintenance Free" mechanical machine!!! LOL Fat chance, darn cars go left and right in my family, but , if by chance you do get this dilemma figured out PWM, let me know, be on your order list post haste!!

The file cabinet is self explanatory..HA ha ha ha... so what ever happened with their design concept with that filing cabinet? Big seller in 1r4N? LOL I suppose it was too alleviate filing and dumping orders for the Sexatary? Ha ha.

Being somewhat trained with in the MET areas, it was obvious that the designer of the Pipe lifter was out for re-reimbursement of the design and cost expenditures it was plainly visible the apparatuses design and functionality was limited, at best, for nothing more than a concept poorly designed and executed. All that money wasted for nothing more than paper weights and abstract art.
"We could have used those funds here with our our group ya Know!!"

Either way, some great examples for Vol 4 of your thread explanations of "Engineering: how NOT to do it" for truth and understanding that the simplest over looked design flaw can lead to catastrophic failures too the point of absolute trashing of the machine and not too mention expenditure's that follow there with in when trying to recoup such mechanical devices.

Thanks PWM, great educational stuff for sure!!

1WW

[PLAYSWITHMACHINES]

You are far too kind

I do have plenty of anecdotes like this, in fact i'm working on part 5....

But i'm too lazy to actually write, it took me ages just to write this first chapter in the 'engineer's handbook'...
http://www.thelivingmoon.com/inventors_group/files/1,1.rtf

http://www.thelivingmoon.com/inventors_group/files/1,2a.rtf

[1Worldwatcher]

I think you should write your repair-related memories, it has the potential to be a best-seller.

Especially with in the Mechanical Engineering technology community, if this is what is happening with in so called "Experienced Designer" rendering's and research, these things could easily been rectified before manufacturing or mass production, When I was in AMT we had done many hours of Luminal Radial spectrometry with air craft frames, may cost a bit more, but sure yileds results for safety and structural issues.

[PLAYSWITHMACHINES]

Thanks, but what really worries me is that these bloody 'experts' are also running things at nuke power plants, CERN etc.

I'm just glad i don't live there
ETA: The one company that DID take my advice saved 45 grand in just one month.

Later on they fired me........

[1Worldwatcher]

Thanks, but what really worries me is that these bloody 'experts' are also running things at nuke power plants, CERN etc.

And whats the worst that can happen with that can opener? 
When they had the issues of the Helium tanks, thought that was going to  be the red flag for not turning it on..LOL If the Engineers there make such a obvious mistake as the engineers for the machinery of what you had provided, well, lets just say we might get some real scientific evidence for what happens when atoms collide with atmospheric pressures of our planet..Ha ha ha.     Swiss Alp's might be viewed as the "Swiss Foothills" fun for the whole family to traverse..lol

I'm just glad i don't live there

I always wondered why the Swiss Alps, heck, they were running smaller ones here in the USA that seemed to producing scale results. Now apparently not abandoned but not being fully operational. Forget the name of the facility that sports the bragging rights, but am sure you are aware of it's existence.

1WW

[Ellirium113]

Comming from working on heavy duty mobile underground equipment I can relate totally to re-engineering stuff that was designed by people who had never even been in the field. One trend I notice is that more manufacturers are integrating more plastic parts and sensors on equipment that works in places the sky rains boulders. Does not work so well a lot of times. We have to keep special towing slings on hand to recover equipment that breaks down or gets buried in the work areas. These have to be recovered by another remote control unit as NO ONE is allowed into the work area. It can be a bit tricky as all the brakes on all equipment are spring applied and must be released by hydraulic pressure to move the units. They have a special hook that has an actuator to dump accumulator pressure into the brake circuit to release the brakes when the tow cable tightens up.

[PLAYSWITHMACHINES]

One trend I notice is that more manufacturers are integrating more plastic parts and sensors on equipment that works in places the sky rains boulders.

Don't get me started on plastic

Fine for Lego blocks, but it's mostly useless in the field. Even the ultra-hard PMMA (Lexan,Plexiglass) will go brittle when exposed to UV or heat, in other words, outdoors

Not only falling rocks, but a lot of my problems with sensors was people standing on them

My standard technique has always been to allow for this and house the sensor in a thick pipe welded to the frame, or a thick plate bolted to the frame. This allowed for easy adjustment of the sensor, and people can stand on it.
The drawback is that it may get knocked out of alignment, which will give problems, but it's a lot quicker, easier, and cheaper than to keep replacing sensors.

I have often replaced nylon bushes with bronze ones

an actuator to dump accumulator pressure into the brake circuit

I know these, they are either ON or OFF, must be a real pig to get them out....and i've had cases where the dump valve lever was rusted solid

And i hate hydraulic oil,.
Hydraulics are very efficient & flexible, & it would be nice to see one with sunflower oil in it, something more environmentally (& human) freindly.

Anyone want to do some research on that?

Been digging in the archives, not much more on BAD engineering, but i've got a whole bunch of GOOD engineering examples from my past.
So i guess that will be 'part 2' of this thread

I might need a new forum, called 'Uncle Luke's Agony Column for Stressed Engineers'
In the meantime, i'm very interested in hearing your stories, preferably with photo's?
LOL

[Back]

I don't have pictures as we are not allowed to take pictures where I work. This happened a few months ago.
On our roof there is a 400hp motor that is part of our cooling system. There is a solid platform where a crane can set it down and a trolley set up to put it in place. they decided that they would not spend the money for a crane. They welded an extension on a fork truck and put 10 55 gallon drums on a counter weight. Stacked skids 8 high and had another lift put the motor on the skids. When they raised it to the roof 2 guys had to stand on the back of of the modified lift to keep it on the ground. The platform is about 5 ft from the roof edge. Then they hooked upped the trolley system and swung it to the platform.

It did work and no one got hurt. I still get cold chills thinking about it.

Bless
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