Is CNC cheating

[Mark P.Participant @markp]

I did.
Mark P.

[blowlampParticipant @blowlamp]

Is this router cheating?

Martin.

[Boiler BriParticipant @boilerbri]

Not cheating at all, did the early model engineers say using a lathe was cheating rather than use a file to shape something?

Bri. 21 century convert 👴🏻

[Michael CheckleyParticipant @michaelcheckley34085]

From experience it is just as easy to produce a part with poor surface finish and poor accuracy on a CNC machine as it is on a manual machine, quite often with costly consequences to the machine and tooling!

I haven't seen many (if any) libraries of parts that one can simply download and machine to produce a model of any kind. Therefore to produce a part on a CNC machine the engineer will have to program the part in G code or model the components in CAD and let the software generate the G code then produce all the fixtures as normal. To do this they will need all the knowledge of the materials and tooling to ensure depth of cut, feeds and speeds are correct as the machine wont back off if it 'feels' its not quite right.

In my opinion it takes more engineering knowledge and skill to produce a good part on a CNC compared to a manual machine. Those that consider it cheating don't have the appreciation for the amount of prep work required before the machine starts to cut. The most used machine tool in my workshop is my manual lathe, the CNC lathe hardly gets used!

Sadly I do not believe that the enormous effort required to get the CNC machine going will be taken in to account in judging at competitions just the same as the effort that goes in to 'own design' projects and engineering drawings e.t.c….needs further consideration to ensure new creations are brought on to the exhibition scene but this is another subject for debate…

[JAParticipant @ja]

Posted by Ketan Swali on 02/09/2016 17:43:38:

I wonder what purpose this thread really serves, other then to create heated arguments in places, setting one person against another?

I wonder if the opening posters objective has now been met. If so, would it be appropriate to request one of the moderators to consider closing this thread, before it really gets out of hand?

Ketan at ARC.

Here, here.

This is enough! If this was a real tea room you could have been chucked out for brawling (punch-up is too good a word).

JA

PS. Contributors  have raised good comments but……………………….. [this is my edit]

Edited By JA on 02/09/2016 21:43:45

[julian atkinsParticipant @julianatkins58923]

Fizzy (Nigel) is one of the nicest guys you could ever know in model engineering. We have corresponded for quite a few years.

Lets get down to brass tacks.

Not that I ever exhibit, one of my locos is hypothetically along side another loco in an exhibition. My tender has been cut out by me with a hacksaw from brass sheet and fashioned. The cab is also a steel silver soldered fabrication cut out from steel sheet. All the valve gear and coupling and conn rods are milled in a very antiquated vertical mill and finished with a file. The frames were hacked out of 3mm steel sheet with a hacksaw and file. The boiler is to my own design, in copper, and silver soldered by myself in my workshop with all flanging plates made with my own hand made formers.

Apart from the pressure gauge, all the cab fittings are tailor made and as close to scale as I can make them. I have made my own injectors.

Alongside is a similar loco but with a commercially built boiler bought in, CNC frames, CNC valve gear and coupling rods and conn rods, a Malcolm High brass kit tender and cab, and all commercial cab fittings and commercial injectors.

How do you judge both?

Cheers,

Julian

[Michael GilliganParticipant @michaelgilligan61133]

Posted by julian atkins on 02/09/2016 22:06:04:

How do you judge both?

.

… as I said on page1 : By the rules of the Competition.

MichaelG.

[John Stevenson 1Participant @johnstevenson1]

This one is is for the hard / easy brigade or not sure if they have the skills.

OK I'm sitting in the bar of a hotel In Luxembourg with the delectable Dr Debs about 1,000 Km from my workshop and all attendent trappings. In a recent post called Florid Script, one of the members is after a binks and Bullows bage for a bike he's restoring.

Another poster put up some script that is very close. So given all i have is a crap hotel computer I took this picture, processed it in a mid priced CAD/ CAM software i have web access to and this is what I got. Sorry you will have to look in my album as I don't have passwords with me to log on to my web space. As I say 1,000 clicks away with no gear.

Now I could post G Code for this but I have no idea what size the finished article is, surround on this one is 40mm x 40mm but even that size could be loaded into Mach 3 and scaled.

Now if you will excuse me i have far more interesting things to do with the delectable Dr Debs,…………………………………..

[julian atkinsParticipant @julianatkins58923]

Hi Michael,

That was a bit of a 'cop out' of a reply?

(I think we will pass over John S's contribution above in the interests of good taste and forum rules. I dont really want to know what John at a foreign bar does with 'interesting "delectable" Dr Debs&#39.

Cheers,

Julian

[Neil WyattModerator @neilwyatt]

I think it's a given that at model engineering exhibitions it is not so much the quality of a model that is being judged but the skill, originality, ingenuity, fidelity and finish achieved by the maker. This makes documentation, particularly of complex items, important.

It does create the interesting situation where, as Julian describes, two utterly identical models may 'score' totally differently – assuming the maker and the assembler have both been honest about their input.

Neil

[Ed DuffnerParticipant @edduffner79357]

If he's in Luxembourg, probably drinking a pint of Stella.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by julian atkins on 02/09/2016 22:58:28:

Hi Michael,

That was a bit of a 'cop out' of a reply?

.

On the contrary, Julian … It was my honest opinion, as already expressed.

If there is a Competition, then the Rules of the Competition prevail.

Beyond that, I think it's all been said in the last seven pages.

MichaelG.

[Neil LickfoldParticipant @neillickfold44316]

This is an interesting thread with loads of varying opinions. It seems to me that a lot do not realise how much skill is required to make something cnc and to make it accurate and have the really nice finish. There is the design or cad skills as well as the cam or cutter path skills. Of course to a great extend the shape as ling as the tool can access it, it will create the geometry. Accurate things need cutter compensation and radius compensation, if not on the machines controller on the cam package making the part. If you can measure the geometry of the tools being used, and create a cutter library with the tools of the correct geometry, then the cam side will create the compensating code. Depending on the equipment being used but the path may need to be modified to compensate for the idiosyncrasies of the machine tool itself. I make stuff on my myford with no digital read out is one end of the scale and make parts on a cnc lathe or a cnc wood router. There are some precision parts that just can not be made by hand and do require the control of cnc equipment to generate the geometry to the level of precision that is required.

The final answer has to be how to you weight the varying skills to make the same item ?

What weight do you give to the person who can 3d draw a propeller with the correct sections and geometry and then program a machine tool and create the tooling and method to make it over someone who hand carves an approximation of the same propeller . The hand carved prop will be not be as equal in performance and will not have the same precision in it's manufacture. The person who used the computer and cnc has a far greater skill set than the person who just carved one up. In this example I know as I have done the hand carved props and they are way easier than the skill set to learn to draw it all up and then create the cutter path. I just don't have the cad skills to draw the props, but do have the cam skills to create the part from a solid model if it were supplied to me as has been done on my cnc router at home.

Which leads to the next part, if you do not make the cad models yourself, then in reality, you have just copied a part and got it produced which is essentially my cnc made carbon props.

Neil

[HopperParticipant @hopper]

I think the poll needs a fourth option: What a bloke does in his shed is his own business.

[Bill PudneyParticipant @billpudney37759]

Beautiful work Shaun……wassitgolike??

cheers

Bill

[Steven VineParticipant @stevenvine79904]

edit – removed post

 

Edited By Steven Vine on 03/09/2016 04:33:49

[Mike PooleParticipant @mikepoole82104]

I see you have been busy since Barbarian Shaun. Nice job yet again. Can anyone be serious that you didn't make this magnificent creation? A CNC mill will make nothing until someone creates a task for it to do.

Mike

[Involute CurveParticipant @involutecurve]

Posted by Bill Pudney on 03/09/2016 03:11:47:

Beautiful work Shaun……wassitgolike??

cheers

Bill

The clappers…..

On my first ride the bike felt surprisingly normal, in fact its only under braking that you notice it doesn't dive much, having said that I've now covered just over 2000 miles on it, mostly on b roads with a small amount of time on track (its a road bike) I've started to notice the differences, it has some advantages and some disadvantages, over the past 600 or so miles I've been playing with adjusting the geometry, in a minuet or so I can alter the rake, trail, ride height, front and back, quicken the steering slow it down induce under or over steer, reduce or increase anti dive, however its easy to get lost in all the adjustments, what I cant get it to do is feel unstable, I've ridden it more or less to the edge of the tyres and it feels rock steady, a couple of odd things are at slow speeds it can tram line a bit, and the front tyre is a fair bit cooler than the back also the steering lock at 15 deg each way is a bit restrictive in tight places.

And its very fast and probably too loud, but I cheat when the cops are about, I pull the clutch in and roll past on tickover……

Next show that's near me Ill bring it along so you can pull it apart ……….

[JasonBModerator @jasonb]

Michael Checkly,Regarding "own design" drawings etc. 20% of the mark goes on these things so something of your own design will score higher than yet another LBSC design.

Julian, assuming both you and the other entrant are honest then when they submitted their entry the would have filled in the form listing any items bought in. The judges will take this into account when marking so your loco will have the potential to score more than the one with bought in parts. I said this earlier in the thread

Think of it like Olympic Diving or gymnastics where there is a difficulty factor – a poorly executed difficult dive could score higher than a well executed easy dive. .

The above is based on what I recall from a talk that was given by one of the judges

Edited By JasonB on 03/09/2016 07:35:03

[Bill PudneyParticipant @billpudney37759]

Next show that's near me Ill bring it along so you can pull it apart ……….

Seriously I would love to, sadly Australia is probably a bit too far away. I'm full of admiration for your work, alternative front suspensions have been of interest for me since the mid 70s!!

Don't get too confused!! ENJOY!!!

cheers

Bill

[Eric CoxParticipant @ericcox50497]

CNC is not cheating, it's a natural progression.

1) Hacksaw and file

2) Milling machine with manual feed

3) Milling machine with power feed selected manually

4) milling machine with power feed selected by computer program

[Mark CParticipant @markc]

That's an interesting concept.

Perhaps the use of converted motorised rotary tables should be considered?

Michael Walters, I take issue (management speak for disagree! ) with the statement that "most" CNC machines are supervised by unskilled operators, it's is my (considerable) experience that they are most often supervised by a senior employee with lots of experience to deal with the problems that inevitably crop up from job to job.

Mark

[Martin ConnellyParticipant @martinconnelly55370]

As stated a number of times in this thread cheating means breaking rules where rules exist, presumably in competitions. It seems to me that as tooling has evolved from basic to CNC the rules also need to evolve alongside the tooling and the follow on from that is that the judging needs to keep up with this progress. I think anyone who has put a great deal of time and effort into designing, drawing and CNC creating a part for a competition entry only for it to be marked down because of the CNC would rightly be annoyed. The judges in modern competitions should have an understanding of CNC manufacturing to be able to make sensible decisions to judge between work done with different methods.

Martin

[Gordon WParticipant @gordonw]

This thread reminds me of the old " 1947 nortons did not have a red plug lead " sort of people.

[John Stevenson 1Participant @johnstevenson1]

They didn’t ??
How awful

[Author]

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