Mach 3 Z-axis problem

[Melchers]

Hi
My Z axis is only moving in one direction and upward only. I am using Mach 3
Thanks for your help

 

[canadianhorsepower]

Hi
My Z axis is only moving in one direction and upward only. I am using Mach 3
Thanks for your help

there not enough info her to answer your question

driver board pin configuration ext ext

 

[idahoan]

Do you have limit switches; you may need to home the machine first. Also if the soft limits are turned on and not configured correctly it may cause it to only jog in one direction.

Dave

 

[canadianhorsepower]

Do you have limit switches; you may need to home the machined first. Also if the soft limits are turned on and not configures correctly it may cause it to only jog in one direction.

Dave

These are good suggestions. But not knowing his set up is hard to answer
properly. I hope he's not using a THB6065 :fan:


Luc

 

[Dave Sohlstrom]

You may have a loose connection on your Dir pins for that axis. Swap Z and X and see if the problem follows. if X is now moving in just one direction check your connections. Step is OK check direction.

Dave

 

[Jan_Rune]

Also possible your direction pulse is too fast. If it moves but not in the right direction that is.

 

[Blogwitch]

I hope he's not using a THB6065 :fan:


Luc

Is there a reason for stating that, or is it just like standing behind a male bovine hoping it comes out in lumps.

If a statement is made like that, it must be backed up with an explanation as to why.

John

 

[RonGinger]

That board is widely viewed as junk. It is very cheap, but also has very slow opto isolators and in some applications they must be jumpered out to get useful results. Its a great case of being cheap instead of frugal. For just a bit more money you can get a much better quality driver. Why drive yourself nuts solving problems you don't need.

 

[canadianhorsepower]

Is there a reason for stating that, or is it just like standing behind a male bovine hoping it comes out in lumps.

If a statement is made like that, it must be backed up with an explanation as to why.

John

John
th 6560 are known to be junk all over th internet use them as an interface board but not as a driver board
type THB6560 review on the internet

cheers
Luc

 

[Blogwitch]

The thing is, I am about to delve into CNC, and can't be expected to know everything about it straight away. A comment like that without an immediate explanation can be very frustrating and confusing.
You have to remember that there are total beginners on here as well as very experienced who may well know what you are on about.

Not being nasty or anything like that, just a bit confused by it.

John

 

[RonGinger]

This touches on an interesting point. I think most of us have limited funds to use for things like CNC conversions, which, in reality are mostly toys for us. So we want to spend as little as possible for our parts. However, there is a difference between cheap and frugal. We are often presented with cheap alternatives that may work, but not well and in the end cause us to waste money when we finally realize the problem and buy the device we should have bought in the first place.

Some will argue that buying cheap allows us to get a start and we can improve later. There is some truth to that, but when you have a resource like the web to research do you have to re-learn every point for yourself?

I really like CNC, and in fact I recognize my hobby is no long model engineering, rather its building CNC devices. I now look for the best value when buying parts, not the lowest price.

 

[Blogwitch]

Sorry to hijack your thread M, but I would just like to reply to Ron's post.

I was going to show my CNC mill build on a dedicated CNC site, but after listing a few of the parts I am going to be using some smart a**e jumped in and started telling me I shouldn't be using such and such a component but to use one costing about five times as much because it is the latest technology. He was very serious about it as well.

The components I will be using are tried and tested over the years to work and work very well, but because he was an 'expert' he said he knew better.

There are always ways and means to obtain your objective, sometimes the cheaper and more robust can be the right way rather than going for the latest gizmos available.

All I want is a basic machine that works, and the guidance I have had from a chappie that designs systems has guaranteed I will get a fully operational machine that will suit it's purpose.

This one upmanship annoyed me so much, it put me off that site right away.

My objective is to use all new parts to build a 4 axis system, including new mill and RT, but the computer and touch screen will be second hand, and the whole build will cost less than 1700 UK pounds. I have now got every part that will be required except for a few cap screws, and it looks like I will be coming out at somewhere just under 1500 UKP, so it looks like I might be able to add an auxilliary spindle with spindle control as well in the original price. It will have the same specs as a commercial unit costing double the price.

BUT IT WILL BE OUT OF DATE COMPARED TO THE LATEST TECHNOLOGY.

Does it bother me, NOT ONE BIT.

John

 

[hanermo3]

Well..
sometimes using the cheap component is just a *very bad idea*.

The TBxx boards are one such case.
So are unipolar steppers.
So is low voltage, say 24 V, for steppers.
So is not using a motion control board like pokeys, csmio, etc.
Poor couplers (ie small ones).
So is direct driving steppers, in general.

It does not matter how much you want an "older" system.
Using something that is not fit for purpose, means that you spent say 1700£, and got 1/10 the results out of it, becuase you did not spend the extra 30-50-60£, which is the difference between a proper solution and something that simply is *not* fit for purpose.

If you use what is a poor solution, you * wont get * something that is almost as good, but a bit slower.

You will get something that cripples the concept, and gives you 10 times less accuracy, repeatability, speed or reliability, for a difference of about 50£, per case, per axis.

For example, a chinese 542 series stepper driver ("2M542" for example) is excellent. 50€/axis.
Sometimes the cheap is good. Sometimes not.
Cheaper than a gecko (251), and better on every sense.
Has:
+soft start
+differential signals
+no noise
+wont energise on back emf

A lot of this stuff is very critical.

A motion control engine (like Pokeys) is an example.
USB anything is not a good choice (just because. Lots of reasons, all with a myriad of preconditions why and why not).
Ethernet connected stuff is better - again for many reasons.

I myself have moved onto brushless servos.
Only 70£ extra per axis, for 5x better performance in accuracy, repeatability, speed, reliability.
This does not mean you need servos.
In this case, steppers will work perfectly well vs servos, just that the servos give you 5x more machine, for an incremental cost of about 70£ per axis.

The motion control engine- is a Very Good Idea and should always be used.

 

[Blogwitch]

THAT is a typical reply from someone who thinks everyone should do as he says with no explanation why.

I know what I want, and have got together the best components that I need. I don't need someone telling me what I should or shouldn't do.

Suggestion is fine, telling isn't.

Nuff said

 

[canadianhorsepower]

Sorry to hijack your thread M,

All I want is a basic machine that works, and the guidance I have had from a chappie that designs systems has guaranteed I will get a fully operational machine that will suit it's purpose.

John

Hi John
I totally understand your frustration. There is giving a warning about
some crappy parts like those THB6065 and trying to tell someone that only the latest technology works fine. What I do for living teach CNC build CNC machine
and Robots so I have a pretty good idea what I'm talking about. We have some old CNC at the college old enough to have DC motors with encoders and being driven buy solid states relay on 12 volts. and we have the latest technology beside it, a Haas that worth over $150,000. CDN . The difference
in our case the price tag. The old one does the job just the same. Bottom line is ........it must be reliable in the environment you are going to use it.
I did build a mini CNC 4x4 x2 inch only to hold a pen it works on 5 volts .
I think that the most important thing is that you make sure that all you will have makes a good package.
good luck

cheers
Luc

 

[Blogwitch]

Luc,
When I talk about old technology, I am talking about what normal people are using nowadays to make their own CNC machines, not technology that has been.
I know that things are progressing fairly fast, and new things are coming onto the market, at a cost. If I wanted to go that way, I have enough money to maybe go a lot further than these super technophiles have already been, and within a year of building and learning I could maybe be talking down to them. If I had the room in my shop, I could afford to go out and buy one of the lastest 5 axis industrial machines, but I don't want to go down that route.
I just want to build a machine that I want to build without some know it all telling me I am wrong in what I do, purely because I have chosen to do it with older technological components, as I know that what I already have will be just fine for me.

Just because I have a larger mill than most, I don't do around saying that other members shouldn't be using a mini mill. In fact, in a lot of my posts, I apologise because I do have superior equipment, and usually show methods they could use to replicate what I have done using smaller machines.

Just a note, I have a morbid hatred of people who think they are better than everyone else in one subject or another. We are here to learn, and that means everyone, even the least experienced member, so if someone can't explain in laymans terms what they are doing, showing or quoting, they shouldn't be posting, otherwise you end up with an us and them site.

Sorry to rant over this, but what happened on the other site I posted on has happened exactly the same on here, and I am deeply hurt over it, because I didn't think such things went on on this site.

John

 

[Swifty]

John, please don't let a few adverse comments put you off this forum. I am with you, when people say to do this or use that it should be followed with a reason as to why it is better that way. This problem occasionally pops up with some members, but you soon learn who they are and generally ignore them.

I too want to build my own CNC mill in the future, but I'm still deciding if I will convert a small mill, or build one from scratch using linear bearings and rails as guides.

Paul.

 

[canadianhorsepower]

John, please don't let a few adverse comments put you off this forum. I am with you, when people say to do this or use that it should be followed with a reason as to why it is better that way. This problem occasionally pops up with some members, but you soon learn who they are and generally ignore them.

I too want to build my own CNC mill in the future, but I'm still deciding if I will convert a small mill, or build one from scratch using linear bearings and rails as guides.

Paul.

John,

I feel sorry but I think you totally miss my point.
I'm not telling you what to do and how to do and what to get , but simply I'M on your side.

Those that believe that if you don't have the latest technology you have nothing makes me sick.

My point was build a system that YOU want and will be satisfied with and thats the goal of a hobby.

Having many years of experience and many resources if I can help you in any way please drop me a line.

I know that this thread has cause you many bad feeling this is why I sent you a PM . I will also post it on HMEM to give my opinion to other members of my opinion
Cheers
Luc

 

[sssfox]

Melchers,

If you are still monitoring this thread, I had the exact same problem on a machine I have been building.

I am using a different motor on the Z axis than on the X and Y, as are most people.

I assumed the pins were the same on both types and I was wrong. I don't remember exactly how I had it connected, but I think I only had one of the coils connected. I had to go back to the site where I bought it, found my mistake and once I had it wired correctly, all is great.

Steve Fox

 

[rodw]

Well..
For example, a chinese 542 series stepper driver ("2M542" for example) is excellent. 50€/axis.
Sometimes the cheap is good. Sometimes not.
Cheaper than a gecko (251), and better on every sense.
Has:
+soft start
+differential signals
+no noise
+wont energise on back emf

A lot of this stuff is very critical.

Great info thanks. I happen to have recently purchased a 4 axis kit with Breakout board with 542 controllers after I killed a Gecko 201. Nice to know I bought good affordable stuff. From memory they were only about $40 each. One day I will do something with them all.