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Convincing the new engineer his idea is a waste of time

implmex

Diamond
Joined
Jun 23, 2002
Location
Vancouver BC Canada
Good morning All:
I have a new engineer to break in at the office of one of my long term customers.

Here's the back story.
There's a piezo switch that goes into a plastic panel for a communications application.
The switch has a round body with a thread and nut and a round flange so you can cinch the nut up from the back to hold the switch in the panel.
The switch comes from the switch store with a skinny oring in case you need to seal the switch for some reason.
This application doesn't need it, so the oring is discarded.

The panel is molded and the opening is too big for the switch, so I make a flanged bushing out of Delrin that's a push fit into the panel and fills up the gap.
I've made thousands over the years with never a complaint.

New engineer, hired fresh out of school, sees the assembly and doesn't like it...he wants the oring in place to seal the joint between the switch and the insert.
So I get a new design with a chamfer on it that's supposed to crush the oring just enough to make it seal.
He's specified a ridiculously tight tolerance on the chamfer that will be a bear to certify to...simple to program and cut but complicated and expensive to measure.
These are 75 cent parts, turned and parted off the bar in one op on the lathe, so they are as round as the stress release of the Delrin allows, and pushing them into the panel forces them as round as the panel hole is.

The kicker is that I cannot see any point to this exercise and the predecessor engineer (now retired) who first designed the assembly couldn't either.

There is a speaker grille with perforations not an inch from the switch that gives full and free access to the innards.
There is a totally unsealed insert just pushed into the panel in which the switch sits.
There are other perforations in the panel for screws and lights and etc etc, none of which are sealed in any way.

So my question to you all:
Do I just do what he wants, charge accordingly and let the shock of the new price be the educational tool that brings him to appreciate the folly of his desire?
Do I argue with him and point out how ineffective his design is for achieving his presumed goal?

What would you do?...I'm not an electrical engineer, and I don't pretend to be one, so my default position is to recognize I don't have the responsibility to determine the fitness of the design unless I'm invited to participate.
After all, there are often very good reasons for an inconvenient design and it's pretty presumptuous for a machinist to just jump in and essentially call the engineer an idiot if he doesn't know the full picture.
Who knows, maybe a customer of the OEM is driving the design, or there's something else to consider.

All opinions are welcome.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
Sounds like a directive from OEM/Corporate office came down the pipeline ... "All electrical devices to be sealed against moisture ingress per spec. XXXXX"
 
make a few the way he wants and after he see them and he is off on some new thing that is sure give him a page in history go back to the old part
 
Pour water on the panel and short everything out. Then turn to him and say, "boy, good thing that o-ring is on the switch".

Seriously though. Bring up all the other perforations and tell him the o-ring will not help. Let him know you can certainly do the chamfer but it's going to add $XX cost and would certainly be pointless. If that's what he wants, it doesn't sound like you can do much else.
 
So my question to you all:
Do I just do what he wants, charge accordingly and let the shock of the new price be the educational tool that brings him to appreciate the folly of his desire?
Do I argue with him and point out how ineffective his design is for achieving his presumed goal?

Like 1yesca just said, make a few "prototypes" for him and with the new high price. The customer is always right, right?
I dont think starting an arguement with him is a good idea, he might become an adversarial problem.
 
I wouldn't have a preference if I were asked to make this, supposing it is not impossible to achieve. Wait til the customer asks if there is any way to bring the price down, then do the reveal.
 
When I was younger and less crabby, I would try to talk to him.
Now that I'm older and much more crabby I would just price it accordingly and wait for him to either order it or question the price.
 
Quote it both ways and include in the description " previously approved and tested design" for the old design and "new design" for the new one. Seeing both prices with no clear advantage may be what he needs to see. I find suggesting instead of arguing usually works better. Life is too short and I'm getting too old.
 
There are lots of people who refuse to take practical advice/experience, and like to reinvent the wheel, and the only way they (might eventually) learn the value of others' experience, is to do things the hard way--over and over.

I deal with this all the time.
N.I.H. "Not Invented Here"...engineers don't like to be "showed up"....:popcorn:
 
I agree with most of the others, it's not your place to argue design if it's not a question of your capability to make. Once the bean counters and/or management hear about the price increase, he will need to defend his decisions to them and it's their job to straighten him out. Your role in his education can be providing him an early opportunity to get in front of a design review team.
 
I may be wrong here, but isn't it kind of stupid to try and seal an o-ring
against a chamfer?

Wouldn't a counter bore make more sense, then all you have to control is depth,
and its easy to measure, and it doesn't even need to be that tight on the tolerance.

-----------------

Training the new guy that works for one of your customers is always fun. Maybe
get him some Scooby Snacks?

Sometimes they turn out to be really good to work with, and occasionally they just
don't learn, but they tend not to last long when they refuse to learn.
 
Not knowing the function, but a semi-educated guess as this is what we do at work (machine and assemble/build electrical units), that seal isn't doing anything. I don't think I've ever seen a box assembly, that we build, sealed with o-rings or rtv or whatever...

However, we do go over and above on aesthetics - minimal tool marks on out side surfaces, good clean fits with screws (ie screw clearance holes are fairly tight), chamfers all matching up in size for multipiece boxes/units. It could be cosmetic, or it could be "the switch has an o-ring so we *have* to use it". :scratchchin:
 
Mostly, I now say don't buck the Brass or when you have a legitimate problem/suggestion he will be resistant to your good/needed advice. In my younger years, I would buck the Brass on small items and that just made my life harder.

It's likely he is right on an O-ring that came with a switch if just to keep dust out, or in the case of flammable fumes blowing up the place and OSHA comes to find O rings missing.

One management strategy is telling the new boss /engineer to go out there and make a change just to let them know you are in charge.
 
Before I make a chip, I'd send the engineer a quote on the new measuring equipment & extra time $$ your going to charge (just on the prototype) to prove the part is what is on the drawing.

Changes afterwards may require new equipment $$$$

There's something rewarding about working with an engineer that can discuss/listen and change a design if it works out better for everyone except the engineers ego
 
I may be wrong here, but isn't it kind of stupid to try and seal an o-ring
against a chamfer?

Wouldn't a counter bore make more sense, then all you have to control is depth,
and its easy to measure, and it doesn't even need to be that tight on the tolerance.

-----------------

Training the new guy that works for one of your customers is always fun. Maybe
get him some Scooby Snacks?

Sometimes they turn out to be really good to work with, and occasionally they just
don't learn, but they tend not to last long when they refuse to learn.

Chamfer grooves are a legitimate o-ring interface, especially in situations where you have minimal clearance and/or space restrictions. Axial or face grooves are generally better, but chamfer grooves have niche applications.

Design information can be found in the Parker Book Section 4-21, page 101. Might be a good opportunity for Marcus to do a little snooping, if the information is out of line with Parker's design recommendations, you might be a bit more confident he's just making stuff up for no reason.
 
Q:[ may be wrong here, but isn't it kind of stupid to try and seal an o-ring
against a chamfer?]

Possible the switch was made for 600 years with no O ring...and then OSHA came along and wanted one so they just added one to the old design.

Possible some day explosion-proof switches will be required in houses because whisky can be flammable
 
I've seen the seal-against-a-chamfer design and it has its place, but it a PITA to get right every time. You people really don't have much imagination when it comes to profits. Never argue with the engineer. Just quote the part and see if they bite. Then, offer to supply appropriate parts to seal all the other switches and holes so the panel doesn't leak. Everybody wins. They seal their panel and you make 10X what you were making before.
 
I agree with most of the others, it's not your place to argue design if it's not a question of your capability to make. Once the bean counters and/or management hear about the price increase, he will need to defend his decisions to them and it's their job to straighten him out. Your role in his education can be providing him an early opportunity to get in front of a design review team.

Yup.....When he get's up in front of the "team" (think shark tank) and he get's his presentation bogged down with cost questions, maybe laughed at, and then told "sit down, we've already decided"....maybe he'll listen to you (next time)
 








 
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