DDSCV1.1 3 and 4 axis offline motion controller

[magicniner]

Who uses tool offsets on non repeatable tool holder, like ER20 on a Chinese spindle?

It's not Rocket Science! All you need to do is bond collars onto your tools to set their insertion depth into the collet and your tool height will be repeatable in a correctly torqued ER collet chuck ;-)

- Nick

[JAZZCNC]

Unfortunately DIY cnc machine will be always one step behind due to the lack of absolute encoders or scales that at all time tell the machine the exact position, even if power switched off. To rely on working offsets on a machine equipped with cheap chinese limit switches is ridiculous. As i said somewhere above on a couple of occasions i measured 0.4mm initial imprecision and now while browsing 3D printer stuff i found some reports that temperature also changes the situation..

Boyan your wrong or doing something wrong.?
I use Chinese prox switches all the time and my findings are very different. My own machine uses them and I'm cutting Aluminium all the time and regularly cock up in some way so then rely on the home switches to get me back into position. They always get me back into position without issue.

its obvious that i don't work in machine coordinates and use different coordinate systems G54 to G59. What i was saying above is that there is no point making fixtures and each fixture to have a predefined work offset, cause the machine anyway will not find properly the 0 just from homing without manually finding the zero.

Again wrong or don't Understand WORK OFFSETS.? Why would the machine need to find new machine Zero for each WORK OFFSET. The machine Zero doesn't change between switching offsets so after the initial First home it doesn't need to be done again.

The switch quality or accuracy as nothing to do with WORK OFFSETS. If the machine is setup correctly then after First Homing it will always know where each Fixtrue is located because it's just an OFFSET from MACHINE Zero. Only if MACHINE Zero position is lost will switch accuracy come into play to enable finding WORK Zero again.

[John S]

We are talking different machines here. Who uses tool offsets on non repeatable tool holder, like ER20 on a Chinese spindle????? Me not.

I do all the while and also teach it other wise if the tool is set to zero it drags it across the top of the work between moves.

It's very simple to follow a set of standard directions when cutting to protect the work, cutter and operator.

CNC isn't new, what is new is everyone thinking their way is better when it isn't.

[Boyan Silyavski]

I can not waste my time to argue with you guys, plus may be you are professional machinists and teachers and i learned about CNC a couple of years ago. Some of it from you. if you say its right for you, ok. If you say all the world does it that way, i agree and would not argue. My mistake then.


But i couldn't care less for all that. I am having a strong opinion what is good for me, what saves me time and how jobs should be run in my home workshop. I have extremely flexible and open mind plus a good memory. I use whatever technique for the moment that best suits me. As i said i mostly use material top as Z0 but sometimes not. So if i hit go to Zero and tool digs in material, bad for me, but it does not happen, because when i program Z0 to be worktable, i program save Z movement higher than material+bit and usually XY0 is material corner not center, so that have never happened. Anyway, machines are not to sleep at, and one should be very awake when working. When i am tired or not in a good shape, i don't use machines


I have tried to use collars as the Kyocera engraving tools come with collars. They are not precise neither repeatable to my liking. So from that time on i dont care for collars. Its faster not to use that way of thinking,.

Another good reason not to use tool offsets and premeasure tools. I have a small case of tools which in total are around 1500euro worth. They basically just cover my pretty basic needs. i don't have 10 000 to spare on tooling. Many times i use the same tool for various jobs, materials plus even for various type of toolpaths on same job. Which means every time i recalculate toolpaths as needed. Which means every different time i insert the tool into the collet just enough for the job. I dont see the reason to have the same stickout just the tool to be repeatable, to make the work offset and so on.

And yes Dean, i use work offsets and i know what they are. I think you should have guessed when i am saying something is not working i am talking about after power loss. I will demonstrate the switch imprecision with video. Hysteresis. That's what i am talking about. But good for you that your switches are working right. What i have discovered is that all depends how you read the switch, from the moment that gets off or from the moment that gets on again. There is difference between both cases. So i found that when i read in forums and people said there:"use simple on /off switches" and i thought " well that's too simple, sensors must be better" i was wrong. Simple switches work better.


So let me again explain the simplest way to Z0 and use the probe with the DDCS controller:

1.put any flat bottom tool in collet and tighten by hand, not by wrench
2.lower Z axis until the bit touches the work table, then move z down 1-2mm so tool moves inside collet up. Stop.
3.hit preprogrammed button to 0XYZ or just use controller and zero Z
4.lift Z axis
5.put probe on table and hit A for probing operation / + is connected to probe -to spindle or machine/, probe has insulator at the bottom
6.probe is touched and probe thickness is rcorded
7.now you can use the probe whenever you like, top or bottom or whatever, cause thickness is recorded

-hit Zero all button again and all of the above is lost. So don't do that or just have it in mind


That's all. So simple. i take back my words and edited the post where i explained the 2 touch probes scenario, as i just found that i was mistaken and in certain cases this will lead to error. I deleted it so nobody makes the mistake . So just use the above said or the below variation, which i find better, but you need a Z setting gauge.

variation of the above using Zero axis setter with known length and DTI:

2. lower until bit touches zero axis setter and all is zero there.
3. if Z axis setter tool is 50mm high/the typical one/ , hit Z0 and enter 50mm, hit enter. Now machine knows its worktable zero


SB shared that video with me in a message, so thanks! I decided to share here. Don't ask me how is done, i know nothing more but will write or call the guys to see if they share.They are Russians or Ukrainians:

[Merlin201314]

Thank you for the clarification, and for sharing the video.

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[Merlin201314]

Thank you for the clarification, and for sharing the video.

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I even noticed that the software limit is not working properly in the controller(or maybe I do all wrong as usual) when I enable the software limit and setup all the traveling limits, the machine do the zero properly, and then the axis start traveling to the setup limit and stop, no other chance to move the machine then, what I'm doing wrong now? Thank you for any help you can give me before I throw the controller in the bin and buy a professional one


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[Boyan Silyavski]

There was something like " ignore limit when home" in the limits menu? Plus i have programmed there to retract 10mm back, i think that was the default.

Now there is an situation where when homing overshoots the 0 and enters in the soft limit zone. What it does then is start to go into the another direction towards the other end limit switch.

Hence generally i find that it's a good practice to disable SOFT LIMIT when homing and then enable it again once homing is done. Or lower the speed of homing so it will stop on time. problem on a big machine like mine, cause you have to wait a lot. Or enter 2-3mm negative soft limit, but problem is that at 4mm it already will hit the sensor.

So i disable soft limit, home and then again i enable it. Anyway, i don't switch off the machine all day long.

On the first machine i have done i had the limits so that they will not interfere with the gantry, but on this one i decided that perpendicular position will give me better accuracy.

[Merlin201314]

Problem solved thank you, was the over shooting that cause the problem, I just added a +/-0.5 mm to each axis and now is perfect, thank you!!

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[Merlin201314]

What about this one guys? Soon this controller will have a new look and setup!! (this is just a quick screen to try the colors

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[magicniner]

You've replaced a graphic with an alternative graphic?

That's "Modding" alright!

;-)