Here is a list of all the postings Steve Pavey has made in our forums. Click on a thread name to jump to the thread.
|Thread: 75mm x 2000mm Belt Linisher Build Thread|
That’s going to be a nice machine when it’s completed - nicely made components.
Where did you go to for the water jet cutting?
|Thread: Spindle speed, vfd and Mach4|
Sorry, it has taken far too long to find the necessary piece of paper.
My parameter settings are:
PD No - setting
1 - 1
2 - 1
3, 4 and 5 - 400 Hz
6 - 2.5 for 50 Hz
7 - 1.2
8 - 220v
9 - 15
10 - 8
11 - set to 133 Hz for air cooled spindle to give min 8000 rpm, for water cooled any figure but below about 6000 rpm gives reduced torque
14 - 5 secs
15 - 7 secs
44 - 2
45 - 3
72 - 400 Hz
73 - 120 Hz
142 - 8.5 amps
143 - 2 pole
You’ll need to check in your manual what each of the parameter settings does, and if in doubt possibly leave some of them at the default, but having said that the important ones to check in your case will be the frequency and no of poles, ie PDOO3,4,5, 72, 143 and 144.
Yes, I’m still around!
I have a file in the workshop with all the paperwork and I’m sure I noted all the vfd parameters - I’ll have a look tomorrow and let you know.
|Thread: Woodwork Router Advice|
Err.. the thread is seven years old, so I think he’s got his doors sorted now. And in any case, your advice is the same as that given by someone else on page 1, post no 10. Just saying..
|Thread: Need to cut long thin strips of steel (& plastic) - e.g. with an angle grinder?|
I’ve skimmed through all the posts so may have missed it, but has anyone mentioned the Gabro guillotine? Their main advantage is that they give a distortion-free result.
My third choice is to clamp the work between two pieces of ply/mdf and cut with a hacksaw, which I see you already do.
Last choice would be a Dremel - way too slow, not good with stainless, razor sharp edges to clean up, etc etc.
|Thread: Endless Repeats|
The BBC, under the guise of TV Licensing, are guilty of harassment and demanding money with menaces. And I’m not joking either. If an insurance company, for example, sent out letters telling people who are not their customers that they risk fines if they drive without insurance cover, or telling those same people that they are ‘under investigation’ there would rightly be uproar. At the very least the ASA would be having strong words with them. But the BBC do this routinely. I have a stack of threatening letters from them. Some of them even resort to ambiguous or misleading statements which imply that owning a tv or an aerial necessitates a licence, which of course it does not.
Attempting to tell them that you do not want their services means divulging your personal details to them, which I am loathe to do. So I have to put up with a letter every 2-4 weeks, and threats of a visit, not from a salesman but from an ‘enforcement officer’. If one ever appears on my doorstep I may not be responsible for the resulting language.
|Thread: Solid Edge Community Edn. - Gen. Qs. Thereof|
The learning process with any software is an interesting topic. My working life has included standing at a drawing board, and much later on teaching various software applications including Photoshop and Illustrator, to both adults and children. Teaching adults is a nightmare - they usually bring with them a lifetime of baggage, and their objections and observations all seem to consist of phrases like ‘why doesn’t it draw this/ that way’, or ‘why has it done that’. Youngsters, on the other hand, simply submit to the way the application works, happily adopting all the tricks and techniques that the adults find so difficult.
Fortunately, us adults have YouTube to help us learn, which is exactly what I did with Fusion360 - laptop in front of me, iPad on the left, watching Lars Christiansen and copying the moves. My previous knowledge of draughting was really not much help, other than being familiar with the concept of X Y and Z planes. After maybe 18 months I’m no expert, but I am able to draw what I need to for the work I do - mostly working in wood, like this jewellery box:
|Thread: Cutting Brass Sheet|
Brass shouldn’t be worked hot in my experience. Some brasses are quite brittle at higher temperatures. Just anneal the brass normally (bring up to a dull red and then leave to cool).
I’ve flattened bent sheet by annealing and then running it through a set of slip rolls - put a slight uniform curve in one way, then turn it over, reset the rolls a little and flatten it out on the second pass. Of course, it means knowing someone with the slip rolls, or spending more on another bit of equipment..
|Thread: Vfd and motor efficiency|
I might be the guilty one - see this thread
There are loads of folk who can give you advice (as I obviously found when I tackled my motor and vfd setup) and when I got stuck in it was really very easy, and I wouldn’t hesitate to do another one. The motor and vfd have run perfectly ever since.
|Thread: Stepper motors|
You’re right Nigel. I did think about this early on in the build, but it really had to be like this because of the space restrictions in the workshop, and the need to have the machine on castors, along with a control cabinet fixed on the wall. I also used some decent connectors from RS rather than cheap imports from you know where! Of course, as you now know I was let down badly by the bloke doing the soldering! At least I know where to look first if a similar problem arises in the future.
|Thread: Leveling machines|
Whereabouts in the world are you Derek? I have a level you can borrow if you’re within a reasonable travelling distance from RH19 near East Grinstead, Sussex.
|Thread: Stepper motors|
Two things that I find mildly annoying - posts that ask questions but the final solution is never posted, and idiots who can’t admit when they’ve been really stupid.
A quick test once it was soldered up correctly and it works perfectly.
So, my sincere apologies for wasting everyone’s time - the only silver lining is that it was actually everyone’s responses that forced my brain to eventually work out where the problem might lie - ie that one of the coils wasn’t getting a signal. Actually, another silver lining is that I have at last used the little oscilloscope that I bought as a bit of an impulse purchase a couple of months ago.
Many thanks for everyone’s help.
This is proving to be a bit of a learning curve - I bought a little ds212 oscilloscope a few months ago which I haven’t used, until today that is. I hooked it up to the DIR and +5v terminals on the output of the controller, 5en used the controller keypad to run the X stepper left and right. The DIR signal is absolutely consistent - high in one direction and low in the other, irrespective of which way the stepper decides to turn**. I also looked at the PULSE signal and it displays a reasonably good square wave. I’m afraid I am not good enough with an oscilloscope to actually measure the voltage, but it’s clearly enough to run the stepper.
the other thing I wanted to do was to hook both up at the same time to see what the time relationship of the PUL and DIR signals was, but something didn’t like me doing that as the stepper didn’t run with both channels connected - maybe something to do with the internal resistance of the oscilloscope?? (Way out of my depth here, so I just disconnected it). I tested the DIR output with a multimeter and it was 4.8v which seems ok. I don’t think I would get a meaningful result doing the same on the PUL output.
I have tried setting both leading and trailing edge active in the controller software, without any difference to the random behaviour, so I’m not that much further forward, except I’m a bit happier that the controller is not at fault.
** To me this suggests that the stepper motor coils are not connected correctly, though I have checked many times that the wiring conforms to the supplied datasheet - https://cnc4you.co.uk/resources/Stepper%20Motor%20Nema%2023%2057HS82-3008B%202.2Nm.pdf
The Ruida user manual is at https://variometrum.hu/pdf/rdc6442g.pdf, though it’s a bit light on details related to configuration.
A small bit of progress - in a fit of frustration at my own inability (!) I decided to remove the wiring to the steppers and drivers completely and start from scratch. The result is now three steppers that run smoothly and don’t seem to get hot. I have no idea what I rectified by rewiring which is slightly annoying, but I’m pretty sure it was a daft mistake on my part.
But I still have problems with the X axis motor not knowing which way to turn, and it hasn’t been solved by substituting a different stepper motor. I have checked the jumpers in the driver - actually no jumpers are fitted to the pins, so it is set to Pul/Dir and active on leading edge. I configured the Ruida controller with these same settings.
I did wonder if the datasheet for the motor has incorrect colours described for the 8 wires, although when I substituted a four wire stepper it exhibited the same behaviour. Another possibility might be some sort of electrical interference, although the cable to the this stepper is the only one that is shielded.
John - thanks, I will have a look at the jumpers. I recall seeing a setting on the Ruida setup menu to change from Pul/dir to cw/ccw mode, and also to change from leading to trailing edge. I assume that these controller settings have to match the jumper settings?
I’m still a bit puzzled by the talk of changing the voltage - I can’t see how this is done without changing the power supply (mines a 24v Meanwell model).
Only the Y axis is connected up at the moment (and that’s the one that’s working fine). Being a laser cnc there is very little load on the motors though, even with all the pulleys and toothed belts fitted.
Edited By Steve Pavey on 24/07/2021 20:58:25
John - I’ve just digested your post. I set the current as suggested on the datasheet. Maybe I need to have another go at trying lower current settings. I have also been wondering about the polarity of each of the four windings, and whether the datasheet shows the correct colour codes. I’m not sure how I can test for this.
I’ve had another play about this afternoon. First I removed the Z stepper (the one that was overheating) - I’ll sort it out later.
Re the overheating Z motor, there is no provision for adjusting voltage. The dip switch settings adjust the current and the microstepping, except for sw4 as mentioned. Clearly it’s overheating because the holding current is too high, but changing the current setting either results in a motor that doesn’t spin, or doesn’t affect the overheating. Maybe two new drivers are needed.
Martin - I’m pretty sure that I have got sw4 set correctly but I will check to make sure.
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