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Author Topic: New to DIY cnc , Looking for some guidance and advice on first CNC  (Read 467 times)

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Offline Darko

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Hello everybody

I am in the research stage of my build and this is what I have so far:

WHAT I WOULD LIKE TO DO RIGHT NOW:

I am looking to build a solid and sturdy MDF-Plywood frame with a 24x48 working area to start and option to machine the vertical edge of the material. In the beginning, I would like to machine hardwoods and some plastic.

So this is what I'm thinking

• 4 CPM-SDSK-2310S-RLN ClearPath Integrated Servo Motor 4 NEMA 23
• 350/500 Watt DC Power Supply Output: 75 VDC - 350W / 500W(fan-cooled) cont; Input: 108-250 VAC
• Y-axis 1500 mm rail and 2010 ball screw with double nut
• Y-axis 1500 mm rail and 2010 ball screw with double nut
• X-axis 1000 mm rail and 2010 ball screw with double nut
• Z-axis 400 mm rail and 1605 ball screw with double nut

• 2 pcs Hiwin rails HG20-400mm with 4pcs HGH20CA bearing blocks
• 2 pcs Hiwin rails HG20-1000mm with 4pcs HGH20CA bearing blocks
• 2 pcs Hiwin rails HG20-1500mm with 4pcs HGH20CA bearing blocks
• I already have a router

The rails and ball screws are Chinese made. (ebay)
(called clearpath customer support and tech I was talking to told me I should not spin the 1500mm 2010 ball screw more than 1800rpm)



WHAT I WOULD LIKE TO DO IN THE NEAR FUTURE:

• Build a super sturdy frame with a combination of aluminum and steel and then transfer all hardware to a new machine.
• Upgrade to a 2.2kw water-cooled spindle
• add MPG
• add rotary
I'm sure there are going to be other things just, can't remember right now.

So this is what I'm not sure about:

So at first, I wanted to go with Acorn board, I really liked their interface and looks like good support, however, only 4 axes, did not want to pair two y-axes together.
My understanding is, with servos, I do not need the drivers, only 5axis BOB

I feel lost here. What 5axis bob should I go with? I'm looking for something that a lot of people use so if I run into the problem I can possibly find the solution from others.

Electronics is not one of the things I know much about, so if you have any suggestions please share.
Forgot to mention, I'm going with the MACH4, it seems like a lot of people are using it.

Thank you very much

Please excuse me, English is my second language

Darko
Re: New to DIY cnc , Looking for some guidance and advice on first CNC
« Reply #1 on: March 12, 2020, 11:48:41 PM »
Hi,
that is quite an impressive hardware list, ballscrews and rails all very good.

I'm a bit questionable about the Clearpath servos, they are good quality, no doubts there, but rather that they are expensive for what you get.

May I suggest you look at B2 series Delta (Taiwanense manufactured in China) or DMM (Canadian manufactured in China) as good quality brands
that won't break the bank and much more powerful for the same money.

I favor Delta servos. A 400W Delta B2 series servo and drive has 230VAC input, no power supply required....they kick arrsse! with considerably more power and control
flexibility than Clearpath's.

Craig
My wife left with my best friend...
     and I miss him!

Offline Darko

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Re: New to DIY cnc , Looking for some guidance and advice on first CNC
« Reply #2 on: March 13, 2020, 11:12:32 AM »
Hi,
that is quite an impressive hardware list, ballscrews and rails all very good.

I'm a bit questionable about the Clearpath servos, they are good quality, no doubts there, but rather that they are expensive for what you get.

May I suggest you look at B2 series Delta (Taiwanense manufactured in China) or DMM (Canadian manufactured in China) as good quality brands
that won't break the bank and much more powerful for the same money.

I favor Delta servos. A 400W Delta B2 series servo and drive has 230VAC input, no power supply required....they kick arrsse! with considerably more power and control
flexibility than Clearpath's.

Craig

Thanks for your reply,
What appealed to me the most is the ease of setup. There are a lot of videos online about clear path servos, and look like they are easy to setup.
I am clueless about electronics so I decided to go this way. I will definitely look up companies your suggesting.

Do you have any recommendations on 5axis controller?

Darko

Re: New to DIY cnc , Looking for some guidance and advice on first CNC
« Reply #3 on: March 13, 2020, 03:28:09 PM »
Hi,
if this is a new build then I would recommend Mach4. All development on Mach3 ceased six years ago, if you are going
to invest several thousand dollars on machine hardware it doesn't make sense to use obsolete software.

I use an Ethernet SmoothStepper by Warp9. It has arguably the best and most complete Mach4 plugin and realtime
features of any of the Mach4 controllers.

I use two single port bi-directional breakout boards. They have no opto-isolation, relays nor PWM outputs, I add those
features as I require. This results in best flexibility and lowest cost but requires you be prepared to make a few
simple electronic additions to the boards.

If you prefer a 'ready to rock and roll' breakout board with all three ESS ports fully developed then the MB03 by
CNCRoom is recommended.

Craig
My wife left with my best friend...
     and I miss him!

Offline Darko

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Re: New to DIY cnc , Looking for some guidance and advice on first CNC
« Reply #4 on: March 13, 2020, 08:12:40 PM »
Hi,
if this is a new build then I would recommend Mach4. All development on Mach3 ceased six years ago, if you are going
to invest several thousand dollars on machine hardware it doesn't make sense to use obsolete software.

I use an Ethernet SmoothStepper by Warp9. It has arguably the best and most complete Mach4 plugin and realtime
features of any of the Mach4 controllers.

I use two single port bi-directional breakout boards. They have no opto-isolation, relays nor PWM outputs, I add those
features as I require. This results in best flexibility and lowest cost but requires you be prepared to make a few
simple electronic additions to the boards.

If you prefer a 'ready to rock and roll' breakout board with all three ESS ports fully developed then the MB03 by
CNCRoom is recommended.

Craig


Thanks for your help Craig.

I will look at it over this weekend.

Darko
Re: New to DIY cnc , Looking for some guidance and advice on first CNC
« Reply #5 on: March 13, 2020, 09:01:36 PM »
Hi,
it has recently come to my attention that there may be a better choice of servo than the B2 series Delta I have recommended.
I personally have bought four B2 series Delta's and am EXTEREMLY impressed. I have one 400W example that I bought
to experiment with and fit in place of one of the steppers in my mini mill, and three 750W (one braked) B2's for a new bulid
mill I'm working on.

The B2 series servos have a native 160,000 count per rev encoder. A later model Delta servo, the A2, has a native 1,280,000 count
per rev encoder but more importantly it is 'dual sensing'. Either servo has more encoder resolution than I will EVER need but I am
impressed by dual sensing.

It means that the servo drive monitors the servo mounted encoder as usual but can also monitor a second encoder hooked to the 'load',
like a linear scale for instance, and incorporate it into the positional control loop. They cost only an extra $50 more than I paid for
the B2 series servos. I actually have no need of this extra capability but if I had known that I could have had it for a little extra
I would have bought them.

There is an even later model, the A3 series, which have a 24 bit absolute multi-turn encoder with battery backup. This means that when
the servo is powered up it will recall exactly where it is, both within one revolution but within +- 128 turns of its nominal home
position....no need to 'home'. They are not yet widely available in the Ebay channels I tend to use so would expect to pay a premium
for them that I can't justify.

These features are simply not available in Clearpaths. You are right, Clearpaths are amongst the simplest of modern AC servos to set up
but that ease of setup has cost the flexibility of application that other brands have.

Note also that ALL servo manufacturers tend to have similar features, if one manufacturer introduces market leading
'dual sensing' say, then a few months later they will all have it.

When I got my first B2 series Delta I intended to program the drive by 'button pushing' on the drive itself. It can be done but
is a very tedious and error prone process. In the end I bought a genuine Delta accessory, a programming cable, that then allowed
me to use the Delta supplied PC freeware to program the drive....so much better!. Just wait until you see the plethora of tuning aids
that comes with the software. Highly recommended. Suggest you allow an extra $50 or so in your budget to get a cable, you only
need one to program as many drives as you have....its well worth it.

Craig
My wife left with my best friend...
     and I miss him!

Offline Darko

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Re: New to DIY cnc , Looking for some guidance and advice on first CNC
« Reply #6 on: March 13, 2020, 10:25:28 PM »
Hi,
it has recently come to my attention that there may be a better choice of servo than the B2 series Delta I have recommended.
I personally have bought four B2 series Delta's and am EXTEREMLY impressed. I have one 400W example that I bought
to experiment with and fit in place of one of the steppers in my mini mill, and three 750W (one braked) B2's for a new bulid
mill I'm working on.

The B2 series servos have a native 160,000 count per rev encoder. A later model Delta servo, the A2, has a native 1,280,000 count
per rev encoder but more importantly it is 'dual sensing'. Either servo has more encoder resolution than I will EVER need but I am
impressed by dual sensing.

It means that the servo drive monitors the servo mounted encoder as usual but can also monitor a second encoder hooked to the 'load',
like a linear scale for instance, and incorporate it into the positional control loop. They cost only an extra $50 more than I paid for
the B2 series servos. I actually have no need of this extra capability but if I had known that I could have had it for a little extra
I would have bought them.

There is an even later model, the A3 series, which have a 24 bit absolute multi-turn encoder with battery backup. This means that when
the servo is powered up it will recall exactly where it is, both within one revolution but within +- 128 turns of its nominal home
position....no need to 'home'. They are not yet widely available in the Ebay channels I tend to use so would expect to pay a premium
for them that I can't justify.

These features are simply not available in Clearpaths. You are right, Clearpaths are amongst the simplest of modern AC servos to set up
but that ease of setup has cost the flexibility of application that other brands have.

Note also that ALL servo manufacturers tend to have similar features, if one manufacturer introduces market leading
'dual sensing' say, then a few months later they will all have it.

When I got my first B2 series Delta I intended to program the drive by 'button pushing' on the drive itself. It can be done but
is a very tedious and error prone process. In the end I bought a genuine Delta accessory, a programming cable, that then allowed
me to use the Delta supplied PC freeware to program the drive....so much better!. Just wait until you see the plethora of tuning aids
that comes with the software. Highly recommended. Suggest you allow an extra $50 or so in your budget to get a cable, you only
need one to program as many drives as you have....its well worth it.

Craig

I am fairly new in-home CNC hobby machines and still have a lot to learn so I'm not familiar with everything you are mentioned here but hopefully, I will catch up.

Thanks for recommending ESS. I'm watching youtube videos now. The ESS/MB3 and MACH4 looks like a good combination.

Can you recommend limit and home switches?

My understanding is I should have them separate. So I should have 8 limit switches (2 per axes), and 3 home switches. Total of 11 switches. Does this seem correct? Should my limit switches be mechanical, and home switches magnetic? In industrial machinery when the machine is powered up it finds X0 Y0 Z0 Machine coordinates, from that point I use work offsets to get around (g54,g55,g56...). Is home switch similar to work offset? In that case, I would not need a home switch because my work offset would change according to my job I'm doing.

Little bit confused about this.

Darko

Re: New to DIY cnc , Looking for some guidance and advice on first CNC
« Reply #7 on: March 13, 2020, 11:39:50 PM »
Hi,
CNC is a learning curve, no doubt.

I have always maintained that a 'success, or otherwise, of a hobby is gauged by what you have to learn in the process of doing it'.
In this regard CNC has been a great hobby for me, I have had to apply myself to many different facets from design to machining,
and the list of things to learn seems longer now than when I started. :)

As far a limit switches and home switches go I would commend that you have separate homes and limits, but be aware very few
CNCers agree with me, most combine limits and homes with sometimes un-predictable results.

I prefer mechanical snap action roller plunger microswitches for homes, I find the natural hysteresis distinctly advantageous
in homing routines. Even without Index homing (if you use servos you will be able to explore this further) I achieve 0.02mm
repeatability. It is sufficient, so much so that I have not deemed it necessary to invest the required time and dollars into Index homing.

https://nz.element14.com/honeywell/bzc-2rq18-a2/switch-basic-top-roller-plunger/dp/1525198

Note that home switches are not required to be at the end on an axis, they can be anywhere within the travel of the axis. There
is advantage in having it near the end but comfortably within the very end of travel. With roller plunger switches I mount
the switch parallel to the axis and the roller plunger is activated by an small aluminum (adjustable) ramp attached to the axis.
This means that under no circumstance can an over-running axis damage my switch by excessive over-travel.

I also had small mechanical (small=cheap) switches as limits on my mini-mill. I had not thought out the consequences of an
over-running axis and I managed to wipe some of them out. I removed them in disgust. I always meant to replace them....
but I've just never get around to it. With good home switches I find that Soft Limits are adequate, and I haven't crashed my machine
for several years.

My new build mill will have G0's of up to 25m/min  and 75-100kg axes so I'd bloody well better have, and well thought out,
limit switches or I'm really going to  screw up bigtime.

For limit switches economical proximity sensors are adequate. Hysteresis it not required or even desired with limit switches.
Given the speed and weight of my axes I may have to have  both a limit (extreme) and a 'slow limit' just inboard.
In the event of an overrun the 'slow limit' would operate first and decelerate the axis and then should the extreme limit switch
operate, then Estop.

Don't be over concerned with work offsets just at the moment. The single best thing I ever did to my existing mini-mill was add decent
home switches. THEN and ONLY THEN do Soft Limits make any sense and likewise being able to save work offsets like G54 ONLY
make sense relative to a FIXED and REPEATABLE HOME location, ie home switches. If you fit decent home switches and maintain
good homing discipline when starting a Mach session that confusion will evaporate and you will look on in bemusement as others
struggle to control their machine without disaster striking because either they have no home switches or are ill-disciplined about
using them.

Craig
My wife left with my best friend...
     and I miss him!