Mechanical engineer: how to work faster? 11

[EighthBen]

I am a mechanical engineer in a wood sawmill company, I am designing various machines. I use solidworks for my design. The problem is this: I am not satisfied by the speed I design things. Here are some aspects I analyzed and noticed:

1. I always try to make the model as "full" as possible - including all bolts, chains, and anything else. This is essential for generating BOMs correctly, and also avoiding design mistakes due to things that were "imagined" differently than they really are. Any decrease in model detail would result in more mistakes (previous engineers, like 3-4 people have perfectly showed how not designing something leads to the need of fixing the final product with angular grinder in the workshop, making much more mess than use). I don't think I can save anything here.
2. I use all the productivity tools: keyboard shortcuts, best-practice design tools and strategies, PDM, fast hardware computer, two monitors, 3d mouse, I know the software deeply (including that I have passed several SW certificates). I don't think I can increase anything the speed here.
3. I have a fair amount of experience in the things I design - I don't have to spend too much time on the phone consulting the suppliers, or the machinery guys/welders to make the design better, and so on. I mean, I don't get stuck often during the design. I don't think I can do anything faster on this.
4. Of course, there are times when I have to do the research: check the solutions of the competitors, consult the suppliers about the things I haven't used before, perform FEA simulation, etc. Also, I sometimes have to explain things to the welders/machinery guys/assembly guys - about what have I designed and what is the intent of those solutions. But - obviously - I will never know everything, and so these communications will always be needed. I don't think I can rapidly save any time here.

Besides, I think I can say that I make fairly little amount of mistakes. I check, and I check, and then I check things again. I must admit I lose some time here (absolutely not significant amount of time, but it adds up a little), but design mistakes would make much, much longer to fix during the manufacturing process compared to the model, so I wouldn't like to risk the increased amount of the mistakes for winning a few hours on design checks.

That being said, I feel stuck in the situation. Even a fairly simple machines takes 1-2 weeks or more to design, and when I look at the finished model - and I can't believe it took that much time. I have no idea how can I make it faster.

If anybody here, the more experienced engineers, could share their productivity strategies, that would be great. I am pretty sure I can not win anything on the software level (as I said I think I can say I know Solidworks fairly well), but maybe some global design strategy could be used to save a few percent of the overall design process.

Thank you for your advice

 

[KENAT]

1. I like the idea of including most items in the model, but think if there are any ways they can be simplified so as to reduce modeling time. E.g on a chain do you model a link then build up an assembly of them? Or just model a 'loop' of the appropriate finished chain dimensions or...

Do you have a good library of parts? Do you use a lot of similar parts so could set up a more fleshed out template that automatically adds certain views or similar?

Do you have any standard calculations set up in matlab or excell or... so you can just plug the appropriate numbers in?

How much time do you spend on other stuff? For instance I have a few standard meetings that suck up my time more than you'd think. I also get involved in supporting quotes that takes up my time too.

How much of your time is spent on non work productive stuff like checking Eng-Tips (speaking of which gotta go...)

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[EighthBen]

Hello Kenat, thank you for your input. You have raised a very good questions - they are certainly very important. Unfortunately everything is already optimized there...

Chains: yes, I model it fully. I need it for the exact length, I usually need a precise length of the chain. Besides, newer version of SW has the "Chain component pattern", which makes the design of the full length chain pretty simple. Besides, I often need special attachments on the chain, so I can't simplify anything here.

Library/templates: yes, it is set up. Standard parts are in the library (bolts, washers, bearings, and everything else). I don't want to go too deep here, but trust me - I have spent a fortune of time optimizing it and now it works fine and fast, and I can't make it any faster.

Calculations - yes, I use SMath - small program, which makes calculations more handy and easier (consequently - faster) than excel. When I have a new project - I use a file from previous project, adapt it, change numbers and make it work. Don't think can make anything faster here.

I use zero (none, absolutely) of my time on web browsing. I never have an unproductive meetings because I work alone - I design machines that my boss tells me to.
I sometimes discuss things with welders/machinery men about how to make the things better, and they often have good suggestions. So these discussions often lead to actually saving time on the long run.

I use Epiforge Grindstone to track my time. I clearly see that I don't have any unrelated activities, but the time it takes to design things make me suspicious that it should be possible to make some things faster... If only I knew how

 

[EdStainless]

You may be down to the finite amount of time that it takes.
I am sure that some guys cut corners and get away with it, but not my style either.

"Of course I don't look busy, I did it right the first time"

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[EighthBen]

Don't say that, I hope there is a hope to come up with something ..

 

[TheTick]

You only need to fully model chains if you're bad at math.

 

[ornerynorsk]

"I use zero (none, absolutely) of my time on web browsing."

Well, I guess we now know that to be not entirely true (a little sharp edged humor, EighthBen, not malicious!)

Depending on the complexity of the machine, several weeks does not sound at all unreasonable. It's far better to be thorough and take an extra hour or two to prevent a mistake that may take days to fix, as you have said.

How have you come to the conclusion that you are taking too long? Is it by feedback from boss/supervisor, offhand comments by someone else, knowledge that someone else in a similar position performs more favorably?

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[dbill74]

Time and experience.

It takes X number of keystrokes to draw a line and there's no 2 ways about it. It sounds like the only way to reduce time on a project/part is to review your design process. I'm not in the business of designing parts of cars with solid works, but something that helps me in designing HVAC and piping systems is to put pencil to paper before I even turn the computer on. (I can draw a line on paper a lot faster than I can in AutoCAD.) Once that's done, I'm less likely to move a line or block 20 times in CAD. The most useful tools I use are the triangles from my college days, a pencil and sketch paper with a scale and calculator not far behind.

Also, start putting together a library of what you've done in the past. I'm sure there are plenty of blocks and details (or whatever SW calls them) you can use from one job to the next, re-use them. (I'm sure you're already doing this to an extent, but find more.)

Take notes when talking to the welders, machinists, assembly guys and keep those notes at your desk. Ask them how you can make plans more understandable and do it. Drawing it once so they understand the first time is better than drawing it twice and having to explain your design in person.

At the end of the day, what works best for me is not what will work best for you, you will need to find a process that works best for you.

 

[EighthBen]

TheTick: I would appreciate if we wouldn't discuss the chain design further, otherwise it would require a completely separate discussion.

ornerynorsk: I mean I must use maedler.com, chiaravalli and other catalogs, find out how some things are calculated, and other things on the net. But I never read news or otherwise spend time during working hours.

dbill74: Yes, I sometimes do that, as much as paper allows it. But maybe I should to it more, because I edit thing quite a lot before I come to final design.

Library - yes, I do it, there are certain automation tools to reuse things in Solidworks and I make the best of it.

Notes: yes, I write a journal with the notes I get from welders and other workers and also a separate journal on how to make a design in the best way in Solidworks. I use them to remember the best practices that worked out.

As you see I tried quite a few things but I am still not satisfied with my speed. I believe the biggest brake is my lack of experience. So I came here to discuss if this could be partly overcome faster than naturally working in the field for years.

 

[TheTick]

One of the hardest parts of design for new designers to get a grip on is appropriate level of detail. There's a time for broad strokes and a time for needle-fine detail.

You seem to know a lot of the fine points of design and your design tools (e.g. SolidWorks). That's a good start, but it seems like you lack a framework for defining and starting a project and moving it through its stages of development. (At least you didn't think enough of it to mention.)

Perfection is rarely worth its price. There is such a thing as good enough. Does a miscount on hardware stop the whole show while someone flies 200 miles to buy it? Or do they get more from the bin? Are you holding up long-lead things like steel purchasing while you count your nuts?

 

[KENAT]

Tick implies a good question is your question:

1) Your 'touch time' while you're actually working on the project i.e. man hours not calendar weeks.

or

2) Total length of time of the project?

You imply 1 but thought I'd check.

Re. not modelling in all hardware, yes for one off or low volume work or similar may not be worth the effort for the sake of BOM accuracy etc. but...

Can be useful in things like making sure you have adequate clearances (Been bitten here when I didn't realize some rivet heads weren't modeled in) or even mass calculations etc. As well as clearly showing where it goes on drawings or work instructions or...

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[3DDave]

There are two means of going faster - either making the parts of the task go faster or replace them/eliminate them entirely with different parts.

Were I hired as a consultant** for your problem, the first thing I would work on making a complete survey of what the final output is required to be like, what the type of input ordinarily given is, and what steps are required going from one to the other. Then we could look at what you think can go faster/ is currently unsatisfactory. When that flow is understood it's possible to see useless tasks and eliminate them and to look at characterizing the amount of time spent on the major tasks with an eye to both entire steps plus any common functions that are repeated across steps.

No different than any software performance analysis.

For example: I originally took 3 weeks to do a swept-volume analysis with a wire-frame/surface modeler. Then decreased that to 1 week with a bit of software I wrote. The third go around was going to be a day or less, but it required understanding the process to move from one speed to the next.

**I don't consult for anyone, so I'm not advertising.

 

[verymadmac]

What do you actually producing from your models, paper drawings? cadcam etc etc.

Often there are numerous simple parts that similar across several products and these are often drawn individually, when a simple table drawing would define all possible configurations. How hard is it to find previously design parts that will do the job. I once worked where they designed subsea jumpers that used large numbers of straight and single bend tubing, they redrew the lot for each project because they used such a poor naming / part numbering convention that you couldn't find them. A couple of table drawings could have replaced the lot.

The first 5% of a programs efforts locks in about 80% of a program costs (number may vary but you get the drift), more focus on the design concept at the start might reduce the project time length.

 

[tbuelna]

"Even a fairly simple machines takes 1-2 weeks or more to design, and when I look at the finished model - and I can't believe it took that much time."

Why do you feel spending 40-80 engineering hours to do a professional job designing and modelling a piece of machinery is excessive? Is your employer telling you that you need to work faster? Or are the machines you design incredibly simple devices, or slight modifications of existing products?

Consider that since we now rely heavily on the fidelity/accuracy of digital CAD models for functions like analysis, QA, manufacturing, etc, it is very important to make sure the CAD model is 100% accurate when released. Better to do the job right than to do it fast.

 

[jlnsol]

There is a command in SolidWorks that I use as much as possible to speed up the design process.
It's the Pack-and-go command. Do you use it often?
When designing machines in SW most part types used will be common and thus used in previous projects too.
There are sheet metal parts (flat, angled, U shape, Omega shape, Z shape and such), rigid parts like round bars, profiles (not the design library parts!), hollow tubes, square tubes and so on. Parts based on extrudes and parts based on revolves etcetera.
So it is a handy trick to use packandgo with replacing the part/drawing numbers and thus quickly generate a new part-drawing combination. Then modify the part dimensions and use it in the new machine assembly.
Benefit is that in the background the attached part drawing is automatically updated. Once the parts are done (many features added like holes or deleted) and you like the assembly design you only have to clean-up the already attached part drawings.

 

[DerbyLoco]

Unless you are being externally pressured to work faster I suspect that you are needlessly beating yourself up. What proportion of the total project cost and overall build time is being consumed by your work - I suspect it will be a fairly low percentage. Good design is an iterative process and it will take time. A few hours optimizing you designs so they are quicker, cheaper and easier to build is time well spent - if you are mainly assembling standard parts it sounds as if you have everything covered.
Finally, and without wanting to appear negative, if you work quicker what will you do with the time you have saved?

 

[jlnsol]

Apart from my previous post about speeding up the SW design process there is another subject.
You call yourself a machanical engineer but you are not!
You are an assistant planner, an assistant purchaser and an assistant outsourcer and also an engineer.
This may sound silly but I read you use PDM.
Synonyms for PDM more often than not are: time-consuming, frustrating, bookkeeping, redundant, managers toy, innovation kill and so on.
In other words: look to the finished model with the eyes of a purchaser, a planner and an outsourcer as well.
Their time gain should be added to your engineering time frame!!

 

[drawoh]

EighthBen,

When you design machinery, or anything else for that matter, there is a certain amount of overhead work required to keep you organized. People pressuring you to speed up will tell you to not bother with this, and they will speed you up, in the short term.

I have repeatedly seen people complete mechanical design, and hand manufacturing a stack of fabrication drawings. They may have saved quite a bit of time by not bothering with assembly drawings and BOMs, but...

[ol]
[li]...manufacturing generated BOMs. Overall company effort was not saved.[/li]
[li]...manufacturing took control of the drawings and BOMs. There was no point trying to reason with engineering, so they didn't. I hope any engineers reading this are cringing.[/li]
[li]...the designs were atrocious. There was no attempt to view the completed system and do DFMA, or to visualize the structure, or to visualize how the system would be managed by the end user. The top level drawings are needed by manufacturing, and they are needed for design reviews and communication with other members of the design team.[/li]
[/ol]

This kind of bungling is harder to do with 3D[ ]CAD like SolidWorks. Then again, the parametric modelling provides all sorts of opportunities for screwing things up.
unless you absolutely have to. How much detail do you need on your chain? Each and every link probably is excessive.

Can you copy and paste from you BOM into your requisition forms? All that effort up from can save a lot of time downstream.

--
JHG

 

[Jboggs]

One word I have not seen in this discussion is "modularity". By asking the initial question you are indicating that you are trying to be aware of and examine your own activities. In all my (many) jobs I have found ways to save time or energy by just looking for any time I am repeating some task. You already said you use previously designed components and sub-assemblies. That's good, but, are you looking ahead? All the time? Are you designing everything with the intent that some future version of your work will be used more than once? What dimensions are likely to change in the future? What other dimensions are affected by those changes? Can you design it so that by just changing one dimension you also change all the others that are affected by it? Do you design it with possible future configurations in mind? Do you organize these pre-planned components and sub-assemblies in some easily searchable database?

For example, one thing I commonly do in SW is to start with basic geometry sketches in which I will try to establish as many of the dimensional parameters as possible for the complete part within one or two sketches, maybe on the top and front planes. I leave those sketches alone and do not absorb them into Extrudes or Revolves. That makes them easier to access later. Then for the Extrude or Revolve sketches I use the Convert tool or relations to link as many parameters as possible to those basic geometry sketches. My philosophy is simple - minimal required changes to achieve the results. If I change something I want everything else affected by that change to change along with it.

I also commonly rename features according to their function, for example instead of "ExtrudeCut14" it will say "Machining_for_Gearbox_Base".

Just some thoughts...

 

[drawoh]

The edit function does not seem to be working. Somehow, I deleted a chunk of my reply.

Don't add unnecessary detail. For example, helices are hard on your video card. Don't model these unless you absolutely have to. How much detail do you need on your chain? Each and every link probably is excessive.

--
JHG