How does your company use confidence level in setting its reliability design inputs and test acceptance criteria?
Given that the confidence level approaches zero as the bounds approach the nominal Weibull curve, what do you consider a minimum confidence level to set as the acceptance...
Some engineers here have begun adding notes to certain component drawings to indicate that the UL report file (no number given) must be reviewed if the design is changed. The intent is to prevent mismatches between the product configuration being manufactured, and that registered with UL. From...
Looking for opinions on a drawing practice related to configuration management: including revision levels of component parts on an assembly drawing. The standards and drafting guidance documents don't seem to directly address it. Advisable or not? How about if the configuration management...
FMEA resources online indicate that a common mistake is to confuse the failure mode with the effect or the cause. I've seen this happen quite a bit, and it's usually due to the fact that the cause-and-effect chain is longer than three discrete items for the failure mode in question. So what is...
In the reference listed below, the author makes a statement about Fault Tree Analysis (FTA) while discussing the use of cutsets:
I was wondering if other practicing engineers using FTA have found this to be true. We currently only use Failure Mode and Effects Analysis (FMEA) as our risk...
What are the recommended run-in procedures for small (~ 1.0 inch gearbox diameter, 96-120 DP gears) planetary gearboxes lubricated with thick (channelling) grease?
In the bearing industry, at least one manufacturer recommends that bearings be run initially at 20% of full speed until the...
I'm trying to do a global-local analysis of a solid model in Nastran for Windows 2003. The global model has been solved, and the original nodes on the sub-structure boundary surfaces have 6dof constraints and displacement loads derived from the output vectors. The tricky part is trying to tie...
A while ago, I came across a reference in Benchmark magazine about Richardson Extrapolation as a useful tool for reducing discretization error. There are quite a few online references to the method, including this one, but I haven't found any which specifically discuss how to apply it to finite...
[Cross-posted from the "Electric motors & motor controls engineering" forum]
Are there any standards which apply to the information and notation contained on engineering drawings of motors (particularly brushless DC motors)? The drawings in question are for procurement control of motors...
Are there any standards which apply to the information and notation contained on engineering drawings of motors (particularly brushless DC motors)? The drawings in question are for procurement control of motors designed by other companies.
ASME Y14.24 (Types and applications of engineering...
Part families are not widely used at our facility, and I think that there's a productivity opportunity to that feature. However, revision control and scope of application are open questions, and I'd like to hear how other users are applying this tool, esp. in a design control environment...
Problem:
- Our legacy doc control system allows checking in and checking out of individual draft, part, and assembly files, but does not manage or maintain links between documents. Therefore, dealing with assemblies is cumbersome. As a result, the users (including me) maintain their own...
I'm searching for a small (~.187 in OD) flexible coupling for a low-torque (~2 oz-in), high-speed (80,000 rpm) application in which the angle between the rotating shafts ranges from 0 deg. to 20 deg.
Of the flexible coupling options that I've explored so far (U-joint, ball, bellows, spring...
[Cross-posted from the "Sharp Tool Engineering" forum]
I'm modeling a custom twist drill in Solid Edge and having trouble creating the tip features which are defined by the following standard parameters:
- lip relief angle
- chisel edge angle
- point angle
Machinery's Handbook (26th...
[Cross-posted from the "Sharp Tool Engineering" forum]
I'm modeling a custom twist drill in Solid Edge and having trouble creating the tip features which are defined by the following standard parameters:
- lip relief angle
- chisel edge angle
- point angle
Machinery's Handbook (26th...
What are some of the most common, most effective, etc. methods of gathering modal data from structural components which are too small to be instrumented with accelerometers?
The part in question is a flat surgical saw blade that is oscillated by a powered handpiece. Its low mass and high...
If any readers have experience with Kaizen and/or Product Preparation Process ("3P") programs in new product development projects:
- What did you find to be the advantages and disadvantages of the methodology?
- How would you compare these concepts to other existing...
If any readers have experience with Kaizen and/or Product Preparation Process ("3P") programs in new product development projects:
- What did you find to be the advantages and disadvantages of the methodology?
- How would you compare these concepts to other existing...
For those readers who use associative part, assembly, draft, etc. CAD files which include deformable parts (i.e. parts which have a free state geometry, and a different assembled geometry): how do you manage those parts with respect to their two states?
We use Solid Edge, which is easy for...
For those readers who use associative part, assembly, draft, etc. CAD files which include deformable parts (i.e. parts which have a free state geometry, and a different assembled geometry): how do you manage those parts with respect to their two states?
We use Solid Edge, which is easy for...
