Denford Triac and Orac cnc machines a couple of years later must have been well received with the ability to program from computer, save the program on disk for future use and/or send the G code program to the machine for execution. I am still using an original DOS program from that era for writing G code programs to send to my Orac lathe and see no advantage in changing for 95% of the work I do.

Emgee

It's rather like the Mercan definition of "vintage" ie something over 30-40 years old. In fact, even g codes have been around since the 50s, with other CNC systems in use well before then.

My Shizuoka CNC milling machine was shipped in 1983, yet it used a well established system – nothing particuarly ground breaking. In those days, I believe most programs were simply typed in to the console (in g code), with programs being backed onto cassette tape or paper tape if necessary.

I expect there will be a few members on this forum who can predate the experience….

Murray

Sorry, wasn't being personal!

Didn't realise they were using Mylar (PET) in "paper" tapes back in the 50s. PET was an amazing invention and was the focus of my father's entire working life at ICI, from tire cord, through polyester fibre (Terylene, Crimplene etc!), artificial leather, drinks bottles and stretched film (BoPET – floppy disks, cassettes, insulators, dielectrics etc). Amazing stuff!

Murray

You can tell it's old. When was the last time you saw an ashtray on someone's desk?

> Didn't realise they were using Mylar (PET) in "paper" tapes back in the 50s.

The PET Stuart referred to is an early 'personal computer'!

Neil

My first job when I came out of the army in 1969 was to machine parts on a "tape" drill. The "tape" was a paper ribbon around one inch wide from memory. All worked well provided the bosses son who did the paper punching upstairs hadn't made any mistakes. I still remember his red face when the Y axis moved on with a brand new 2" (I seem to remember) still in the 'ole. Like a carrot it was and so effortless

Rik

but they were a plumbers nightmare, blowing seals and leaking and then the concensus was to concentrate on servo and stepper controls

And hot and noisey, as well as taking up a large amount of room for the oil tanks, coolers etc. And very, very finicky about cleanliness – machines were shipped with "flushing blocks", which were used to replace the servo valves to allow the system to be flushed for several hours if the hydaulics had to be worked on.

But before reliable, high power electronic switching devices, there was little option if you wanted a high torque servo drive. Mostly hydraulic motors driving ballscrews, but some (certainly some Newall borers, probably others) used hydraulic cylinders. Taken plenty off & replaced them with modern electric servo drives (and managed to interface a modern control to the old servo valves on a Newall cylinder driven jig borer) in my last job.

Mylar tapes were only used for the Diagnostic and Parameter tapes on the machines I was set on to learn the maintenance of in 1977 – much too expensive to use for day-to-day operation. BTW, if you come across any unused rolls of 1" tape, don't bin it – it hasn't been made for ages & there are still a few die-hard users who will pay whatever you want to ask to get hold of it !

Nigel B

My degree final year project in 1987 was a program to translate between the ISO standard language for NC machines at the time (ISO5700?) and the Heidenhain TNC controller language. So translating from 1 non g-code language to another. Completely pointless.

It's good to see that the language that survived had such deep roots, and that some bits survive from so early.

Regards

Richard.

The first NC Mill I saw at Vickers Weybridge was run off paper tape about 2" wide and was PNEUMATIC, i.e.: a jet of air was detected being blown through the oblong holes punched into the tape – would that have been PNC ??
The next machine that I saw (not allowed to touch) was the Med Head mill, see **LINK**
BobH

Anyone remember plugboard capstan lathes. They always looked like black magic to me

Oh yes – very profitable for me as an apprentice was a Hepworth plugboard capstan lathe. This used a Herbert (No. 4 Pre-optive IIRC) as it's base with a Hepworth plugboard control. The control had a couple of dozen TTL logic circuit boards, which were frequently "iffy" – many boring hours sat waiting for an intermittent fault to appear to use signal injectors, heat gun, freezing sprays etc. to try & identify where the problem was. Usually though (& this was the profitable bit for me) I had to take the suspect board to Hepworth's works outside Holmfirth (our works was in Brighouse) to have it run through the test rigs there. I ran a sub-250cc motorcycle & got the small car mileage rate, so a nice run out in the middle of the day paid for my fuel for the week.

In the late '80s I comissioned & trained on a couple of new CNC VMCs installed in Czechoslokvakia (pre the end of Communism). One of the milling machines there used 35mm movie film as the "tape" – a very basic control moved the axes in sequence to limit switches, the relevant switches being punched onto the "tape", which was then spliced to be an endless loop. The programmers I was working with brought out the reel of film that they had been given to use and, holding it up to the light to see a few frames, it was obviously an old propoganda film, with an actor made up as Lenin on a podium giving an animated speech.

Nigel B

No, if you look at Stuart's second post, you will see he referred to Mylar punched tape. The reference to PET is the name polyethylene terephthalate (aka PET), which is the chemical name for what is known as "Mylar", polyester, Terylene, soft drinks bottles etc etc. Your confusion Neil, not mine.

As for the computer form, I probably know PETs better than most. Back in 1980-1981 I was using CBM (Commodore Business machines) PET (Personal Electronic Transactor) computers in experimental real time, closed loop industrial control for a 10 month placement in the Controls Development Group within ICI Petrochemicals Division – the advanced R&D function based in the Wilton headquarters. That was in my year out before I started at (sorry, "went up to" ) Cambridge to read engineering.

BASIC as an interpreted language is inherently unsuited to real time control, not least due to the fact that any error in the code or an unexpected input would cause a syntax error and crash the program. We got around this by isolating the keyboard with a machine code routine that only allowed specified characters to be accepted. This required the EEPROMs to be reconfigured (change the keyboard interrupt address etc), although I can't pretend I did any of that part of the work personally. We developed a structured, consistent method for writing the programs and did rigorous testing of the various modules. At the time is seemed quite a step forward.

This solution was a much more cost-effective solution than the alternatives (PDP11 etc) available at the time by an order of magnitude or more and worked well from a technical point of view. We had the real "top end" stuff like the dual floppy drives, high res graphics cards and IEE488 interfaces – and the 80 column display(!!). We even had one of the top of the range 32k(!!) models.

Not long after this experience, we enjoyed the "home computer" revolution, with the Commodore 64 (essentially the final iteration of the PET evolution), Dragons etc in every bedroom of the world and unstructured, poorly designed(?), hacked code at every turn. That pretty much put me off computers and software until perhaps the early 90s with the exception of my final year project which was a self-tuning 16 channel PID controller based on a CPM machine (The Comart Communicator!!).

Murray

Edited By Muzzer on 18/06/2017 15:27:18

Technically BoPET, where the material is stretched.

You may recall those plastic things that held 6 packs together. If you stretched them, the material would neck down but not fail. Clearly in the process of necking down, you have the same force but now a smaller cross section area, so the stress (force/area) has increased, yet what gives first is the unstretched material remaining. In other words, the yield stress has increased significantly.

The same process is used in the production of the fizzy drinks bottles. They start out as little test tube shaped mini bottles, then they are blown out with compressed air to full size (inside a mould!), after which point they are immensely strong.

Mylar film is similarly stretched out and becomes very tough and much stronger than the basic moulded material. My word "strong" isn't very technical but it's been a long day…

Murray

Edited By Muzzer on 18/06/2017 21:21:07