Where do you think most of the quality issues come from? We've all heard or seen one guy with a vehicle get 150k trouble free miles and another with the same vehicle in the shop 10x in one year. Is it a combination of engineering, quality of parts and assembly or do you think most of it stems from the person who is putting it together? Most of the assembly process seems automated, but human hands are still doing many of the jobs.
Vehicle Quality Issues - where do they initiate from?
- Thread starter buster
- Start date
Complexity of the system.
Engineering an assembly is great within the modeling software, engineering for manufacturing is a very different topic and relies heavily on the tolerance stackup.
You can't just decrease the tolerances because maintaining +/- .001" is much more expensive than +/- .005" and if everything is within spec, but is at the extreme of the spec, the stackup gets messy. Complex systems tend to not work well at stackup extremes.
Engineering an assembly is great within the modeling software, engineering for manufacturing is a very different topic and relies heavily on the tolerance stackup.
You can't just decrease the tolerances because maintaining +/- .001" is much more expensive than +/- .005" and if everything is within spec, but is at the extreme of the spec, the stackup gets messy. Complex systems tend to not work well at stackup extremes.
Yes. Ha Ha.
Lots of places problems can come from. If it was always the same place they could fix it. For example:
There was a series of I believe Toyota Tacoma that had frame rot - the steel itself turned out to be defective.
One of my Nissan's was subject to a class action for timing chains. Seems the tier supplier of the chain links ran the dies too long, causing burrs on the chain which wore out the guides. So QC at the tier supply level. Nissan also redesigned the chain to carry more oil, for good measure, so maybe it was more than one problem.
Our new Toyota the power seat gear motor made a terrible noise at like 500 miles in. I assume someone simply assembled the gear motor improperly. Toyota simply replaced the entire seat back - no more issues since.
Lots of places problems can come from. If it was always the same place they could fix it. For example:
There was a series of I believe Toyota Tacoma that had frame rot - the steel itself turned out to be defective.
One of my Nissan's was subject to a class action for timing chains. Seems the tier supplier of the chain links ran the dies too long, causing burrs on the chain which wore out the guides. So QC at the tier supply level. Nissan also redesigned the chain to carry more oil, for good measure, so maybe it was more than one problem.
Our new Toyota the power seat gear motor made a terrible noise at like 500 miles in. I assume someone simply assembled the gear motor improperly. Toyota simply replaced the entire seat back - no more issues since.
Sometimes the vehicle is in the shop 10x in the same year because the dealership couldn't fix it right the first time. What good are TSBs if dealership employees won't bother to read them?
Poor maintenance at the factory and parts suppliers. For example imagine machine which cuts cam ledges into a cylinder head and another which measures the cuts. I suspect both machines have to undergo periodic maintenance and/or recalibration. Now imagine a decision to delay that downtime and run just a couple of more units in order to meet a delivery goal.
Engineering and parts quality are the big ones, both can lead to assembly problems too, but if a design is simple as possible with accurate parts, then usually they are easy to assemble!
My pair of Focus wagons are the only cars I've owned two of, and the consistency of the parts quality is pretty impressive. The same things broke at quite similar mileages! Everything seems to be assembled well but certain parts fail even in cars built 18 months apart.
My pair of Focus wagons are the only cars I've owned two of, and the consistency of the parts quality is pretty impressive. The same things broke at quite similar mileages! Everything seems to be assembled well but certain parts fail even in cars built 18 months apart.
all to true, I worked at an VW factory years ago and you would not believe what went on.
The Rabbit / Golf plant in Westmorland?
If so, and if you're a VW aficionado or car person in general, you should read, "Getting the Bugs Out" by David Kiley.
Truly a AA+ read.
If so, and if you're a VW aficionado or car person in general, you should read, "Getting the Bugs Out" by David Kiley.
Truly a AA+ read.
One need only look at Hyundai/Kia for the answer. It's all of the above. Sometimes, the engine is made well, the components are free of flaws and the assemblers + machines do perfect work.
Other times, parts are not properly cleaned, the crank gets dropped, the exhaust valve alloy has flaws and insufficient engineering development was "the name of the game".
It should be no surprise that Toyota engines have consistently good results, despite erroneous claims that their modern versions are not as good. Toyota gets every step right. With the bottom of the barrel brands, you are at the mercy of the wind and weather. Some days are good, others not so much.
Truedelta undertook some real world data crunching with regard to long term reliability. We should not be surprised to learn that Toyota comes out on top, and the best overall model is the Camry. It is one order of magnitude more reliable than a VW Passat.
dnewton3
Staff member
I worked in manufacturing and engineering for 25 years. I can say this ...
Some issues are design related.
Some issues are manufacturing related.
Some issues are supply chain related.
Some issues are labor related.
There is no one single cause; if it were that easy to identify, it'd also be that easy to fix.
Some issues are design related.
Some issues are manufacturing related.
Some issues are supply chain related.
Some issues are labor related.
There is no one single cause; if it were that easy to identify, it'd also be that easy to fix.
Starts from the beginning. You need to implement six sigma/zero defects approach and or a TQM strategy.
Raw materials - WIP (Work in progress) - Finished goods. This is a a very basic explanation but you need to ensure you source your raw materials from a quality supplier with a track record. Then, your WIP, you need to ensure employees have the same training and dedication and then factor in variables such as stress, issues at home etc. Finished goods, well, they need to be inspected before being shipped out. Again, make sure your suppliers and employees have in place and practice the above quality measures.
Again this is a very simple example and as long as we are humans mistakes will be made.
Raw materials - WIP (Work in progress) - Finished goods. This is a a very basic explanation but you need to ensure you source your raw materials from a quality supplier with a track record. Then, your WIP, you need to ensure employees have the same training and dedication and then factor in variables such as stress, issues at home etc. Finished goods, well, they need to be inspected before being shipped out. Again, make sure your suppliers and employees have in place and practice the above quality measures.
Again this is a very simple example and as long as we are humans mistakes will be made.
Here is an unmodified Ecoboost engine that was coupled to an automatic transmission. How did this happen? Why do some fail and others take an unrelenting beating? In more than one case, the suspect is a Chinese rod, valve or rod bolt alloy of inconsistent quality.
It starts with the bean counters.
Many very well engineered parts/products have been ruined by them, in the parts/products themselves, in manufacturing shortcuts taken, and in part/component vendor procurement just to save a few pennies here and there. Just like tolerance stackup, there is bean counter stackup as well.
Many very well engineered parts/products have been ruined by them, in the parts/products themselves, in manufacturing shortcuts taken, and in part/component vendor procurement just to save a few pennies here and there. Just like tolerance stackup, there is bean counter stackup as well.
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yep, that's the one. I worked there years ago, the place has been gone now for years replaced by a Sony plant, not sure what's there now if anything.
It’s called consistency and repeatability of the production process. It’s actually not about setting tighter tolerances as many seem to think, but ensuring the process and consistently and repeatedly achieve the set tolerance or whatever other outcome is desired.
That’s where six sigma come in. It has been statistically established that most processes will generate very predictable results when they are within six standard deviations from the nominal value.
That’s where six sigma come in. It has been statistically established that most processes will generate very predictable results when they are within six standard deviations from the nominal value.
Bingo! I'm a big believer in employees at all levels pay attention to what managers pay attention to and to produce a consistently reliable vehicle management involved in design, manufacturing, supply chain, and labor must pay attention to QA and hold their subordinates accountable. My educated guess is Toyota gets this right across more of these domains when compared to VW.
