Adding a Fourth Axis or Indexer to your CNC

Fourth Axis or Indexer?

When we talk about a fourth axis it means that we have four simultaneous axis X Y Z plus one other.

That means you can move them all together (the moves are simultaneous) and they are all timed together.

It’s a bit like trying to pick your nose and scratch your arse at the same time. You can get mixed up and poke your eye out.

CNC Machines are much better at this kind of stuff than we are.

Below is what happens when you program an X Y Z and C (rotary axis) move in one block of code.

The one below is on a lathe so the Z works  the same as the X above.

In this program it’s just a Z C move or on a CNC Milling Machine it would be X C

Simultaneous

In the above example just the two axis (Z and rotary) are simultaneous..

If your machine has a simultaneous fourth axis, sometimes known as a full fourth axis.

On the position display you will see X Y Z but you will also see C (sometimes A or B I’ll explain later)

A full A B or C axis will be programmable in .001 degrees. That’s one thousandth of a degree (very small).

Typically G0 C185.326 rotate to 185.326 degrees

If a machine has an indexer and not a full fourth axis it normally won’t be shown on the position display.

Another thing to note about a full fourth axis is that it doesn’t stop at 360 degrees and start again at zero.

Angle wise 0 and 360 are the same but if you are talking simultaneous then it’s continuous.

Are you confused?

This is my pet goat his name is Beelzebub I named him after a famous politician.

Let me explain. In the example above (the fourth axis example, not my goat) you want the fourth axis to rotate more than once.

You programme C1440. which is 360 x 4 and it turns four times and the other axis works simultaneously.

So if the other axis (X) is moving 60mm. For each turn it moves 15mm. Just like a 15mm pitch thread.

Ok you get it now? Good. Very good. Just when I am starting to loose my fuckin patience with you.

The number of times I have to beat my students with sticks these days is getting more n more.

So What’s an Indexer

When we talk about an indexer on a CNC machine this means we have a rotating axis but we can only move it to a position. This can be 1 degree or .1 degree depending on the machine tool.

Whilst these are really useful you can’t do all that clever shit that you see above. So don’t get confused especially if you are footing the bill for a new or second hand machine.

Check the minimum angle you can index. If you have a part and it has holes at 10.5 degrees and your indexer is one degree increments then you’re knackered (or fucked but I have decided not to swear in these articles anymore).

You could be disappointed. “Sold a pup” as my mother used to say. I”l have to ask her what the fuck that means.

Don’t you just love them. I know they’re little portable shit machines but soo cute. Make lovely Christmas gifts.

Not on Linkedin though for fuck sake. Anyway enough gratuitous crap.

Retro Fourth Axis

Retro, a bit like sick and gay, this word has a totally different meaning to an old guy like me.

Political correctness to me means voting for the correct political party.

Now with regards to an indexer retro means it’s added on, like sticking a spoiler on your old Mini Metro.

What retro doesn’t mean, is wearing your dad’s old Parker Jacket and thinking you look cool when you actually look like a prick.

Anyway when you add an indexer to an existing machine you control it by a dedicated M code from the CNC Machine.

Your indexer will have it’s own little control system and programme. This programme will be a series of index moves probably followed by clamp and unclamp command.

The machine will send an M code to the indexer and won’t continue until it gets a signal back from your indexer saying it has completed whatever it is doing.

Now your CNC machine doesn’t give a flying shit what the indexer is doing, but it won’t carry on until it gets the signal back saying it’s complete. It’s like wall papering the hall through the letterbox, unless of course you are a gynaecologist.

You do have to be careful with all this stuff but it’s a relatively cheap way to get a programmable indexer.

Haas Fourth Axis

Haas machines come really well equipped and it’s usually relatively cheap to add a full forth axis years after you bought the machine.

After all they used make the bloody things, before they made CNC machines, I think.

They do a great range of add on bits n pieces.

Extras

This is all stuff to consider when you buy a CNC machine new. It can be really expensive to add at a later date as an extra. So bite the bullet, grasp the nettle and get one with your new machine. Give them my name so I get a fat commission.

Simple As ABC

A rotary axis can be called A B or C. This will depend on which axis it runs through.

On a vertical machining centre like this one the centre of the fourth axis runs along the X axis so it’s called an A axis

If it runs through Y it’s called a B axis. And Z well……. try n guess.

Full Fourth Axis Useful or Just Bullshit

In the real world there aren’t actually loads of jobs that need a full simultaneous fourth axis. Radial slots maybe radial engraving.

When you start talking about indexing to angles and just doing stuff, well there are loads and loads of uses. For example with a square part you can get all around it just by indexing so your part can come off complete.

Leave Your Fourth Axis Setup

Don’t forget to set your fourth axis as far to the right as you can so you don’t have to keep taking it off.

You should consider a base plate That way you can mount your indexer outside the machine stroke.

By mounting your indexer I don’t mean trying to shag it by the way.

Taking a fourth axis  off and on can be a real pain the arse.

Also don’t forget to use a G10 to store the work offset. If you don’t know how to use G10 then be ashamed of yourself and read this.

Add an Indexer or Fourth Axis

Adding an indexer or fourth axis to your small CNC Machine will increase capacity and allow you to rotate parts to get to areas you didn’t even know were there.

Here’s a free advert for someone

Surface Area

If you consider the long cube on the axis above. You actually have four faces so it can be a lot of surface area when you add it up.

A lot of people make these cubes themselves and it can save money like baking your own cakes or performing your own keyhole surgery.

Thanks

Congratulations you are the first person to get to the end of one of my articles without being bored shitless.

If you feel you have been affected by any of the issues raised in this post or need CNC Counselling then contact me.

If you want to learn to programme CNC Milling Machines

Siemens 840D Sinumerik training

Look no further Contact CNC Training Centre

Fanuc OT More Fun Than You Think

CNC Lathe with very old Fanuc OT control.

I sometimes think I have the best job in the world apart from a few people like rock stars, pornstars and people who work in chocolate, and beer making facilities.

Everyday I get to work with interesting friendly people (apart from that bloke who knocked me out for accidentally deleting all his programmes). There are some very unreasonable people around. It took him less than three weeks to re-programme all the parts.

This week I worked at a company that makes lights n light fittings for posh restaurants and hotels.

Now I have never been allowed in a posh hotel or restaurant so I was amazed at all these fancy lights. The quality of the products these guys produce is absolutely stunning.

I got to train them on one of these.

Now I know what you are thinking “Lucky Dave, that’s a beauty” but I can see straight through your sarcasm and please don’t keep calling me fuckin Dave, it’s David.

Anybody who reads my articles, and there’s only three of you,will know that I absolutely shit-faced love these old machines.

This one looks a bit shabby I admit but it’s previous user was not so gentle with it. A good service and some re-alignment and it’s back to to the workhorse it was meant to be.

Not to mension excellent training from me.

It’s old, but then so am I so lets not be ageist.

Got to be honest here. I had forgotten some of the little quirks to the old Fanuc OT control.

Dig Deep

Once you get your head around it there really ain’t much it wont do. There are variations on this control and this one didn’t have all the bells and whistles. You know like rigid tapping and macro.

I mean who needs all that complicated shit. I’d much rather keep breaking taps and not be able to parametrically control a CNC programme with the flexibility to make varying sized parts. Not to mention probing and automatic tool measurement. No no no bollocks to that keep it simple.

Joking aside dig deep and make sure you’re using everything it’s got.

I’m a great believer in working with what you have n with a body like mine believe you me you have to.

Anyway let’s get on with it.

MDI On The Fanuc OT

The MDI screen is not like the newer controls where you just write into programme O0000.

You type in commands and it fills in details on the screen.

You have to input each word of code separately, then when they are all on the screen hit cycle start or this green button.

Sorry but you are going to have to get used to all the shit pictures because it’s all I have access too.

If you don’t like it there are way more interesting sites than mine. Not about CNC by the way but there are so many good porn sites out there these days.

I mean it bores the arse off me, and I’m the one writing this crap!!

Haas Tip of The Day on Youtube is amazing try that.

Word of Warning in MDI

If you input a position move and a tool change in MDI. It will make the move first then do the tool change.

Wouldn’t recommend it.

This MDI is not like the newer ones where it’s a programme it’s just one page that gets filled in.

It’s OK once you get used to it.

Programme Copy Fanuc OT

Editing is a little bit shit but once you get used to the protocol it’s not too bad. Try to change the way you look at this. I mean use the lower cursor arrow to search.

This is because the keys are quite cumbersome so if you can get into the habit of keying in the address, for example G or M, you can find the next G or M.

Or choose something more specific like G71 and then press your lower arrow to search.

I always feel sorry for these guys working in the chip shop where they have this thick polythene membrane over the keypad for the till. It’s pretty random which button they hit.

I paid £40 for fish and chips the other day (mind you the way inflation is going it was probably correct).

I said to the young lad serving me “is this fish cooked” he said “I’m sure it is”. I said “well it’s eaten half my fuckin chips”

Anyway this Fanuc keyboard was a bit like his. Maybe I should work in a chip shop, wonder if you get free chips?

Enough About Chip Shops

If you make yourself  use the search key it will make the whole experience a lot less frustrating.

To copy programmes is long winded but worth the effort, press the extra edit key and then move to start of the bit you want. You then press the first cursor button. Move to the end of the bit you want to copy and press the other cursor button.

More on this.

Programme Zero O0000

You then get to execute this. It’s all then placed into programme O0000.

Go back to your original programme and use the merge key to either merge this programme where the cursor is or add it to the end.

You can also change the programme number O0000 to another number, making a new programme.

When you are copying programmes you can use the ALL key for copying all of the programme.

When you use move or copy you can input a programme number so it does not go to programme O0000

This is not meant to be a full explanation but just to give you some idea of what can be done and get you excited.

More details here

So what the fuck is programme zero? Programme O000 is the programme number that the Fanuc control uses as a sort of clip board. When you use the merge button this programme O0000 is what it merges.

It even has find and replace.

End Of Block

My control had asterisks instead of semi colons for EOB (end of block)

This would annoy the shit out of me but it’s not my machine and I really couldn’t justify altering it and putting the users future in jeopardy.

If you don’t like this then just change parameter 10 bit 1

It really makes no difference it just looks different.

OCD

I often get accused of having OCD. People go around saying “oh it’s OCD”. When you just keep your work area tidy.

No fuck off, I like things tidy I’m a fuckin engineer.

If this is you then stop saying it. If you ever meet someone with real OCD you will be shocked. It’s a terrible condition it’s not just about keeping the knives straight in the bloody cutlery draw.

Rolls Royce 1971

When I worked at Rolls Royce in 1971 the guy who trained me was Ex-RAF and an absolutely amazing guy.

Reg his name was.

Reg knew I had a reputation as an apprentice for having absolutely no interest in work and just dreamt of being a rock star all day. Bit of a prick in those days but Reg didn’t seem to mind that.

This Really Is Me

Reg was a clever guy gave me a full sex education and taught me more about good engineering practises, in the six months I was in his care, than I have in my whole career.

He had a more subtle approach to training me. To start with he just used to talk to me and what stories he would tell. This guy was a fighter pilot in the second world war. The stories were amazing and mostly could not be used on this page. Even with my very low editorial standards.

He was talking one day about how much the guys used to swear and how ridiculous it got.

He was home on leave one day and the whole family had lunch together. Grand parents, aunties and uncles about 15 people for dinner.

All was silent as they all started to eat lunch, after they said prayers as they did in those days.

“Pass the fuckin salt” Reg said in a load voice completely forgetting where he was.

I found this story so fumy. There was an embarrassed silence and then everyone chatted on as if they hadn’t heard.

This guy believe it or not had a pet shop in the precinct in Coventry which he ran in his spare time.

He had a pet monkey. He told me how the monkey would sit on his shoulder whilst he served customers. The monkey found it amusing to stick his prick in Reg’s ear when he was serving customers.

I was so charmed and in ore of this guy that before I knew it I was assisting him to build gearboxes for the Nimbus Engine

He taught me basic skills like wire locking and how to correctly use spanners.

Before long I was assembling gear trains. I was really into motorbikes so a lot of the skill was transferable to what I was doing at home.

Fortunately i didn’t have one of these (Norton Jubilee) My mate did and it was an unreliable piece of crap.

The most important thing he taught me was the importance of keeping your work area spotless clean and all your tools neatly in place.

He knew where every spanner rachet and Allen key was and could drop his hand straight on any one without even looking.

If one tool was missing or out of place he would notice immediately. Imagine if you left a spanner inside an engine!

Oh and my workshop is still immaculate as you can see.

Being tidy is pragmatism not obbsessive compulsive dissorder.

OCD I rest my case.

Other Exciting Parameters Fanuc Ot

You might want to fuck with some of the other parameters like these:

Parameter 40 bit 0 displays programme description in Library

Parameter 4 is to protect O9000 series programmes

Chamfer and Radii Fanuc OT

This control has the ability to add a radius or chamfer to a programme.

Just programme point to point and then add C or R as an after thought.

You learn something new every day.

My daughter is autistic so everything is taken in a very literal sense. I  witnessed a friend drop straight into this trap. He was explaining how good it was to use a roller to paint furniture. yes, he said, “you learn something new everyday”.

Oh dear methinks.

I knew what was about to happen. “Mmm” my daughter said “what about yesterday?”

He thought she was joking, but no, she wanted to know exactly what he had learnt every day of that week.

When he said “It’s one of those things that people say”. I knew he was digging himself deeper and deeper into the shit.

I decided to pull him out. “It’s just a stupid neurotypical saying. It’s just not true”.

What I Learnt Today Fanuc OT

On this machine you don’t need a comma when you use R and C.

G1 X50. R10. 
Z-20.

When I saw it I thought “mm where the fuck is the comma?”

Turns out there is a parameter to change it. (That’s what I learnt)

Don’t get this confused with G2 and G3. All you need with this is to programme the shape without the corner radius or chamfer (point to point) then just stuff in the pesky little C or R afterwards.

Authors Note:

I also learnt that there is no such word as learned. It’s learnt. Should have listened at school. (Smart arses please feel free to give me an English lesson.)

A Hidden Button Fanuc OT

Bet you didn’t know about this button.

Now I can tell you for sure there is nothing good about getting old. No no, it’s definitely the shit end of the chronological stick. It’s fucked up and I don’t like it.

You definitely get more patient with age. Like standing in queues. When I was young after five minutes in a queue I would rather remove my own appendix without anaesthetic than to stay another second.

Nowadays I just change into my slippers (which I have with me at all time in a carrier bag for life) and light up my pipe. Happily waiting for hours to be told “oh you can only do that online love”

People even call you “love” when you are old.

Have you ever noticed the No at the bottom of the F key? Anyway, I know the suspense is killing you. Well…. if you are on the offset page or the parameter page, when you press this key you will see No flashing on your screen. You can now input offset or parameter number and it will search for that number when you press input.

Now I know you’re thinking “this twat should find something better to do with his time” and you’re probably right.

The thing is if you force yourself to use all these little shortcuts then overall it will make a real improvement in efficiency. Oh and I’ve been watching you, you really need to up your game. Pissing around with that iphone all day.

It Will Make You More Efficient

Not to mention repetitive strain injury.

I often say to people who I’m training “I just read the manuals that you just can’t be arsed to read” and then charge you for training. They just laugh, mmm.

One More Really Important Thing

Now I know I’m banging on a bit about chip shops today but what the fuck is this thing about having gravy on chips!!!

Fuckin disgusting. Now I know it’s a northern thing and I know you northerners have some strange traditions but frankly this should be outlawed by public health.