Fabricate or simulate?

[John Collins]

There is much discussion about simulation and how to get the best out of such software, and I applaud the help given. However I cannot believe that the solution will be found through simulation software alone. In another thread, Fletcher (I think) mentioned how he went over old ground from time to time and covered the same ground as others who had gone before. I too have experienced this many times, but sometimes you see something the second time that you either missed the first time - or you realise you had wanted to try but had forgotten because another idea occurred in the middle of construction. Those who fabricate will know what I'm talking about.

In my experience you cannot simulate the experience of physically holding pieces of a mechanical construction in your hands and suddenly perceiving a new variation on their arrangement that you believe holds promise for a solution.

Of course I haven't succeeded yet or you would know! But I could show you photos of some of my past failures - I counted 22 discarded 'wheels' in my workshop yesterday, so full of holes that they looked like the night time sky and yet every hole represented an idea or an arrangement that failed at that time. I have hundreds of pieces of metal of varying lengths with assorted holes that were used and used again over the years. I'm absolutely certain that I would never have thought of all the different arrangements if I had relied on simulation software alone - or even a pad and a pencil.

Finally, although I am envious of the very attractive test rigs that others have made, my 22 'wheels' have offered a basic test rig that has worked just fine. All I need is a piece of MDF (medium density fibre board, made out of compressed saw dust I believe). I cut myself a round disc and mount it on a simple frame which consists of two uprights fixed to a flat square piece of timber. On top of the uprights is a pair of plastic brackets for fixing plumbing pipes to walls. The 'wheel' has a threaded rod inserted through a hole in the middle and that is dropped into the two brackets and away she goes or rather should do but hasn't done so far.

I can fix anything - any arrangement to the 'wheel' and use them over and over until there are so many holes that sometimes I drill into an existing hole resulting in an enlarged one and then it's time to discard that one and begin on a fresh disc.

Just my experience. I know some such as Ken would probably love to be able to fabricate but is unable to at this time but I would urge others not to rely too much on simulation software - it cannot beat fabrication.

John Collins

[ovyyus]

John, I have to agree with you. Although there are advantages to simulation software, like being able to try some mechanical design variations faster and with less cost, there are other things that just can't be done easily.

Some examples of the limitations of simulators is the difficulty in dealing with things such as wind, pressure and thermal gradients across a kinetic structure. Certainly it can be done, but not easily with simple software and rudimentary programming knowledge.

Nothing gives you the 'feel' of a piece of wood like getting a splinter :)

[RonS]

I have six wheels with so many holes they barely hold together, and boxes of levers with weights that I have varnished and painted so they will look good when it runs, so far it's not turning, but I saw a different arangement of levers from working with them that I did not see from drawing them on paper and I have drawn a lot on paper. I am about 75 % reassembled to see if it's was a good idea or not. OK, mine is a version of MT13. I can't get the no 13 out of my head. It's a fun hobby but what will we all do when someone gets it. Oh I was in Hermiston Wa last week and the next town is Stanfield, so I called Ralph and stopped in to say hello He too has wheels around his shop and several battery powered PM toys for inspiration. Hi again Ralph.
RonS

[graham]

Hi there John.
My workshop too has a graveyard of parts that I cannot seem to throw out yet . Many years of ideas and dreams remain unfulfilled .
Disbelief that a brilliant ideas that I had concieved failed to mote down in the workshop.

There 's nothing wrong with testing out ideas with a simulation program it saves a lot of time and expense if you use the program properly .
There is one member of this group "Jim Mich" who claims to have discovered the secret of PM using the WM2D simulation program , but as of yet he is is keeping his discovery close to the vest while he sorts out his patent protection.

We shall just have to wait and see if his success is due to a glich in the program or his use of it.

Real success will only come when it is put together with real parts by capable hands and then runs like the devil

Graham

[rlortie]

HI Ron,

I appreciated your visit and hope you enjoyed our little tour. If you make it back this way please stop in

To All,

When Ron dropped by He expressed interest in my suspended wheel, Unfortunately I recently had robbed parts from it. It was in a disassembled state. I am putting it back together to make sure the next visitor is not disappointed as it is definitely a conversation piece of work.

As I have stated more than once I am a hands on type and agree with John. I call my version of WM2D "Wood , Metal, & 2 Days.

For the Trivia lovers, MDF is as John explains.it is made of three sizes of ground wood chips and a formaldehyde based resin. It is produce on a long flat conveyer belt as follows. First all three grades of chips are separately mixed with resin. then on moving belt a layer of fine is laid down. next a layer of medium and then the course. then another layer of medium followed by the fine. This then goes through a pre-press that bonds it well enough to hold it together. Then the continuous sheet is cut into 24 to 26 foot lengths, loaded into a stacker that feed it into a high pressure heated press of multiple plates. From this stage it is then
allowed a short cooling time before going through a multi staged drum sander.

It is then cross cut and ripped to desired lengths. If for general purpose sales the popular size is 49X97" This give a 1" tolerance for blade kerf and still have the right standard cuts for cabinets ETC. It may be purchased in 3/8, 1/2, 5/8 and 3/4" thickness at any lumber yard.

My present cost runs $13.60 a sheet for 3/4" material and is very cost effective as it can be used over and over. It's weak point is, it does not hold a screw or nail edgeways. I drill a 1/4" hole through face near edge and fill with a !/4" dowel. I then screw into the dowel.

MDF does a very good job of holding glue joints together, Most all white or carpenters glue will bond so well that any attempt to separate will produce a break other than the glue joint.

MDF should not be confused with underlayment or aka particle board.Although they look the same the difference is in density. MDF by standard specs weighs 50 lbs. per cubic foot while particle board weighs in at 35 pounds per cubic foot.

For those wishing a little more class, order MDO, which is MDF with a vinyl or plastic lamination to the face.

As some of you already know you can build a hefty wheel using 50# board.

Ralph

[rlortie]

Quote from Graham,

There is one member of this group "Jim Mich" who claims to have discovered the secret of PM using the WM2D simulation program , but as of yet he is is keeping his discovery close to the vest while he sorts out his patent protection.

We shall just have to wait and see if his success is due to a glich in the program or his use of it.

Jim,

Does this imply that you are seeking patent before building a POP? Or do you already have it sitting in a well hidden dark corner covered with foam so as not to be heard.

My recognition of your talents and thinking would lead me to believe you would build working model before spending the time and expense of seeking a patent, that is unless you are going for a concept patent.

Ralph

[Wheeler]

Anyone know the easiest way to make a wheel out of MDO?

I Have used my plunge router by putting a screw or pin in or on one hole at the base or somewhere close to it, Then I use my 4 ft. T square or any low profile alum bar to act as the connecting rod as I spin it.
The diameter can be easily adjusted to any size wheel within the range of the T Bar.
Pin the other end at the center of half the diameter.
It seems to make a perfect circle, but the last half inch is trickie because it suddenly is cut free from the whole piece of MDO, and you must be ready for the danger of the plunge router catching on the wheel or the outside of the cut MDO. But it works for me.

[Dave]

I think John's comments are well taken. Today's designers are very much reliant on the computer, ie key board drivers. The computer has made it easier to implement some designs but it has placed too much reliance on simulation and not enough proper thought process up front. I can simulate most any thing given enough variables but usually there is something that the computer doesn't know. The computer is help solve the problem not solve the problem on its own.

[Georg Künstler]

Hi John,

fabricate is the only way to be successful. If the simulation software covers not all physic, then you cannot simulate the wheel, and therefore you will not try to built it. I said it several times before, the software is incomplete. It allows you to simulate what had been thought before. New things are not programmed. The software only used beaten path.

If I had trusted to the simulation software I were not able to finish my wheel. Now, after having the solution, I can adapt this software.

The future has begun

Georg

[ken_behrendt]

John wrote:

Just my experience. I know some such as Ken would probably love to be able to fabricate but is unable to at this time but I would urge others not to rely too much on simulation software - it cannot beat fabrication.

Well, while it is true that I am still a little too shaky to do a build and was forced to begin learning WM2D to satisfy my innate need to construct something while recovering, I have found that I now much prefer to use a CAD program...at least initially. Yes, I know they have limitations and there are some designs that can only very roughly be approximated with them, but it was almost immediately obvious to me that their use can save one a LOT of their precious and LIMITED supply of time, energy, and resources when conducting PM research.

Of course, I do not consider CAD programs as a substitute for constructing a physical model, because it is only a physical model that will satisfy everyone that the principle of one's PM device is valid and it only a physical model that will be usable in the real world.

However, if I had had something like WM2D available to me 40 years ago, then I believe that I could have eliminated ten times (or more!) as many designs
as I eventually did the "old fashioned", hit or miss way. Quite possibly, I would already know the secret of Bessler's wheels!

I intend to continue to use WM2D even after my health is restored to the point where I can build physical prototypes again. Not as a substitute for them, but as a quide that will let me know when its time to build and what to build.

In my case, however, this approach may be more appropriate than for others because all of my designs tend to be, although unique (I hope!), rather simple in design. Someone else with a more complex approach may absolutely need to build a prototype, but even in these cases a CAD program can still offer some assistance in testing a portion or subassembly of one's design.

ken

[Fletcher]

There 's nothing wrong with testing out ideas with a simulation program it saves a lot of time and expense if you use the program properly .

I agree. It's only a guide, an advanced form of pad & pencil & it has the advantage of being instantly recalled in detail, for review or refinement.

There is one member of this group "Jim Mich" who claims to have discovered the secret of PM using the WM2D simulation program , but as of yet he is is keeping his discovery close to the vest while he sorts out his patent protection.

I'm sure jim_mich will clarify here. IIRC he said he hadn't simulated it on WM2D but had made a CAD animated program instead with the maths & physics to back this up.

[Jim] Does this imply that you are seeking patent before building a POP? Or do you already have it sitting in a well hidden dark corner covered with foam so as not to be heard.

My recognition of your talents and thinking would lead me to believe you would build working model before spending the time and expense of seeking a patent, that is unless you are going for a concept patent.

I think he has said that he is going for patent b4 POP.


My computer drive has many designs & my workshop holds the bones of many dinosaurs long since dead. One, cannot be relied upon without the opinion of the other.

[Ed]

... I have found that I now much prefer to use a CAD program...

Actually you are talking about CAE not CAD, but I agree that simulation software is only another tool and not a substitute for building.

John, you wouldn't fabricate something without any prior figuring, on paper or such, would you? The simulation software is just one more tool and, just as you say you get a feel for things by building, you also can get a feel for things by really understanding the simulations and what it is you are trying to do.

I am not advocating anything other than just using the means one has available, that make sense at different stages of an idea, and that can get the job done. If one's budget doesn't include money for MDf, bearings, power tools, etc. than one has to make due.

Personally, I try to balance my research with real building, simulation and manual calculations to get a real feel for what I'm trying to accomplish.

Use whatever works for you. In the end it's the results that matter!

-Ed

[cw]

Hi John,

You make some good points and I agree that nothing beats hands-on tinkering to inspire creativity and new ideas. Mother nature is what she is and software is just a cheap copy. :)

Some people (like myself) may lack the resources and/or time though to construct a lot of physical models. For anyone in this category, simulations provide at least some means of testing concepts. I've used WM2D enough to know that it's flakey and shouldn't be trusted to reflect the real world. None the less, it is useful for testing some ideas. I would never rely on a computer simulation to "prove" anything and believe a physical model is the only real proof.

The PM "solution" may not be found through software simulations alone, but they may serve as a stepping stone in that direction. Just my $.02...

cw

[Dave]

Again simulation is talked about being first then building.
First comes the thought process, don't start key board driving until you have thought and sketched the solution through. You may find that it has problems before you fabricate. If you cant find a problem then start the simulation.

[Ed]

Again simulation is talked about being first then building.
First comes the thought process,...

I don't know where you get this from? It sounds to me like stating the obvious. I can't speak for others, but if I discuss an idea and show simulation results to the forum, it is implied that I started with an idea and worked up to a simulation.

There may be some that just start plunking things into the simulation software and see if things "stick", but I think most people (by nature) start with an idea and a thought process, and then work up to simulation and physical build.

-Ed