not too sure what a star point is, how do I connect it to the metal braid screening?
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not too sure what a star point is, how do I connect it to the metal braid screening?
here is some reading for you.
https://en.wikipedia.org/wiki/Earthing_system
This has been talked about many times on here try a search !! Read some of the build logs etc you don't seem to take advise when offeredQuote:
Originally Posted by ravihotwok
Advise welcome, instructions even better. Searching is great, but is something can be answered in a simple sentence then that saves a lot of time. Will do a search now and see what I can find.
That wiki link explains a lot. Except the best way to go about physically achieving it.
I now understand what a star point is. Can I splice into each of the motor cables just to expose the outer metal braid, then solder/heatshrink a cable to it which can then me linked to a star point in the box?
the screen is just metal that picks up the noise and passes this noise back to ground as current, so as long as you have a good connection to ground that is all you need. so use your initiative and solder a wire onto the screen and connect it to gnd.
how you do it is up to you and depends on how messy you can accept.
Great Gary, I understand that. Im pretty sure I can do that nice and neat and finish off with a bit of heatshrink to keep it all covered up.
Ravi, like this:
Basically you are building a path for any electrical noise that may target your cable and give problems, so it can leave the system.Quote:
Originally Posted by JAZZCNC
Awesome lee, instead of doing it like that I will do it a bit further back as ive got plugs on the end of my cable which connect into the planet control box. But I will put a earth point where the plugs go into the box, so there will only be a short length from the motor cable to the box for earth, should look reasonably neat. Thanks chaps for explaining in laymans terms, helped a lot. Will crack on later tonight and report back with some more pics
G'Day Ravi, as one layman to another, I know it can be tricky getting succinct info on this subject.
Here are a number of references that I have kept on this subject, that I hope may be of some help.
I'm enjoying your thread, keep up the good work!
Andy
Grounding and Earthing
Electric current through a wire creates a magnetic field around it. Current flowing in opposite direction creates an equal and opposite field. Keep the wires close, ideally twisted together, and the magnetic fields cancel out, don't transmit interference, and are resistant to outside magnetic fields for the same reason (rather simplified but the principle is true). Pass wires through separate holes and not only do you lose that "cancellation" effect because the wires are further apart, but you now create a magnetic field between the two wires that can induce (= create) a current in the metal box between them, which is exactly what you don't want to do. I can bang on about differential signalling and common-mode rejection, but the simple model is pretty sound to understand what's happening.
http://www.mycncuk.com/threads/5036-...7665#post87665
Grounding and Earthing often creates a lot of confusion and to some extent depends how old you are. But you don't connect your DC ground to the Star point which is the point where all the screens connect to and then that is connected to the AC earth. The reason for the Star point is to get rid of earth loops (or ground loops if you are old).
Sometimes you have more than one DC power source and again sometimes you have to connect the various DC power -ve together. Hope this helps a bit.
http://www.mycncuk.com/threads/7662-...3631#post83631
But in electrical engineering context words Ground and Earth differ in scope.
Ground is a general term that refers to a reference potential against which all voltages are measured.
Earth is same as ground but used in context of power systems because the ground here is implemented by burying copper conductors deep down into Earth.*
Since Earth has minerals, moisture and it has practically infinite volume, the current flow is only limited by contact resistance between ground/earth conductor and soil. Because of this, on the distribution side, the neutral is connected to earth. On receiving side, fault current from one of the phases can flow into the local earth conductor and make its way to the neutral at distribution side. Apart from being a sink for fault current, the Earth conductor also serves as a return path for instrumentation systems.
http://www.mycncuk.com/threads/7662-...3653#post83653
different disciplines treat the words different such as in electronics PC boards often have a ground plane that is not connected to earth but to DC ground or signal ground in this case ground is not earth.
http://www.mycncuk.com/threads/7662-...3653#post83653
don't forget the chassis ground, signal ground, RF ground - there are loads of grounds but they do not have to be connected to earth :)
http://www.mycncuk.com/threads/7662-...3653#post83653
Grounding is a whole subject in itself! In simple terms, the issue is that wires and connections aren't perfect, and don't have zero resistance. Hence although you might connect things together to form a common ground, there are always tiny differences in voltage across them. This is especially the case when large currents are involved, of if there are multiple paths between the grounded items. And since ground is your reference for everything, then this can cause issues in operation.
http://www.mycncuk.com/threads/10456...8433#post88433
Thanks very much Andy, very very helpful, Ive got the limit switches to try and sort tonight as well, im trying to run them as far away from the power cables as poss, but in some areas they will be very close especially the limit and power cables on the z-axis. Will have to see how I get on. Buying some MDF this weekend to make a sturdy table top and enclosure with a blow/extraction system, once thats done i can route the cables properly, when the cables come in close contact with each other I will try and think of some sort of extra shielding to help reduce interference (if thats the correct word).
Cheers for the positive comments :-) Helps keep my chin up with the build.
It's not a recommendation, but this works for me:
From the top, spindle power (screened CY) runs in the same cable guide as the Z limit proximity switch (unscreened 3-core) and Z stepper power (screened CY). Next level down they are joined by Y motor power and Y limit/home switches. These run together in about 2m of cable guide before splitting to go to various places (junction boxes, sockets on control box). Where screened cable is used, screens eventually go to star point in control box but screens are only connected at one end. Each cable guide also contains an earth wire which connects to the metalwork at each end of the cable guide to make sure that there is a reliable earth connection right from the spindle to the control box so I never rely on electrical connections via the linear bearings. As much as anything, this is to make sure that the touchplate connection is reliable.
I have had a couple of problems with the proximity switches but these are switch issues which I have been able to fix (and possibly due to using some of the cheapest switches available on eBay) and I have had absolutely no noise issues whatsoever from day one. Maybe it's luck although apart from ignoring advice to run power and switch cables separately, I have generally followed good wiring practice. I do also use 24V for the proximity switches (which my motion controller is happy to accept) and that also helps noise issues.
Sorry, but all the soldering joints you made looks like really bad work. I would redo this. Get a solder sucker like this...Quote:
Originally Posted by ravihotwok
Attachment 22344
...remove every large clump, make sure your soldering iron is not too large but is designed for the purpose and that the solder wire is thin enough, quickly melting and floating well on the surface. The surface must be clean and the tip of the soldering iron must be kept clean using the wet sponge. I clean it after each and every soldering point.
Here are a few do:s and don't:s:
Attachment 22345
You need to practice on something which is not going to be used, not something which you need later on for reliable operations. Get a magnifier and check/fix every point. You will get a lot of headache later on if you box this and start using. Even if it works now, it may fail at any time.
Thanks mate, why are they bad? in the link you sent me it stated when the older balls at the top of the connection and doesnt make contact with the metal ring on the board it is bad, but the ones I have done which are balls but they are making perfect contact with the board rings? I will revist this though just want it clarifying so I fully understand mate
solder sucker bought and arriving monday
I can't spend time marking every point, but like I said, get a good magnifying glass and have a look at each one of them. Unless they are not looking like the one marked A in that picture I posted above, you have to redo it. Most of the ones I have seen in your pictures (not only in the one I linked to) are bad. If you have a ball it means the solder wire did not melt and floated out, or there was dirt on the surface or the iron or you did not heat up the wire you solder AND the surface you solder it to and so on... Just google "how to solder" and you will find millions of answers regarding soldering with pictures and Youtube video, so I will not go into more details.Quote:
Originally Posted by ravihotwok
Very good. Make good use of it, buy a few spare tip and filters also.Quote:
Originally Posted by ravihotwok
Ravi,
Just a couple of notes:
1. There is to much solder on each one
2. Get yourself some soldering flux, liquid preferable
The flux and soldering go hand in hand, when the solder "flows" better (you'll see the diffrence) because of the flux, it just works and you'll see what I mean about there being to much on each joint.
Flux isn't cheap depending on what you get, however if you get liquid flux you simply apply a very small amount, so it last's a long time.
If you keep application to a minimum you wont need to do a lot of clean up, in fact look for no-clean flux, I like to use isopropanol alcohol to clean any soldering/pcb jobs I do.
Links below for what I use, just dip your tip in the Kalafonia tin before each pass.
ALCOHOL BASED SOLDERING LIQUID FLUX SMD/RMA REWORK, REFLOW, REBALL, NO CLEAN
COLOPHONY/KALAFONIA Limited offer 40g for the price 20g tin Solid soldering flux
IPA 100% | 1 LITRE | Lab/Pharma. Grade | Isopropyl Alcohol/Isopropanol (99%) 1L
Look forward to seeing the rework :)
sakes lads ive just bought some flux but its hard stuff, will up load a pic in a mo. Im going to spend sat afternoon redoing these solders, thanks for explaining it in detail, I thought it balled due to me putting enough into the area and the solder had no where else to go so created the ball. Now I know this isnt the case and can revisit it with the knowledge of what im trying to achieve.
On another note, I want to buy new steppers a mine appear to be proper crap. Any recommendations for 3 motors that will fit my machine? budget of £120 for all 3?
Ok, well the better value option to what I linked would be to buy some solid Rosin like this eBay - Rosin Resin and mix it with the Isopropyl I linked to above, brake the rosin up and add to the Iso untill your happy with the viscosity.Quote:
Originally Posted by ravihotwok
Here is a video on that:
https://www.youtube.com/watch?v=iv_2ULCmA28
Don't know what flux you've got but i'm sure you can change its viscosity, again the Isopropyl is what you want but nail varnish remover is made from Acetone and Isopropyl is what you get from the Hydrogenation of Acetone, if you've got some nail varnish remover you could try mixing some with the flux you have already, keep in mind though that they put perfumes and other softeners in nail varnish remover so it wouldn't be the purest of fluxes.
I would just order some Isopropyl, its so handy for other things, Hexa the company I linked don't mess about so it should be with you sharpish.
CNC4YOU is still the best place both on price and service, the motors are of the lowest inductance we can find vs other things, link below.Quote:
Originally Posted by ravihotwok
Link: https://www.cnc4you.co.uk/Stepper-Mo...YGH301B-Nema23
If you're soldering new components, the flux in common solder should be more than enough to ensure a good solder joint. Any common solder you buy for electronics should be flux cored.
It must be over 10 years since I last used separate flux, and that was dealing with vehicle earth points that had been exposed to a couple British winters. I've certainly never used it on any PCB I've soldered.
I have been working with electronics since the mid 70's and as long as I remember, there have ALWAYS been flux in the solder wires I used. I never bought any separate flux ever in my life. As far as I know, flux in liquid or hard form is only used for soldering pipes and other very large surfaces, not PCB.Quote:
Originally Posted by m_c
So far the only advice he's had is to get a solder sucker and start again, clearly there is more going on than that and he needs more experienced input, let's give him that instead shall we.
Flux cored or not something isn't right and it's probably a combination of things, additional Flux I think will help Ravi along in getting better joints, additional flux has been used in the SMD and rework/reflow arena's for years and for a very good reason!
What solder wire are you using?
Ravi, using additional flux cannot hinder the soldering process and can only assist you in doing a nice/better job, don't tell anyone this but that is the reason they put it in solder wire in the first place :).
Your soldering iron needs to be hot enough, balling up like that can come from the iron being too hot or cold, I'm betting yours is to cold, some lower end irons heat up but they don't do very well at staying hot once you start using them, this happens with low power irons too at around the 25w range, when you are trying to solder bigger components.
However my go to for most jobs is now a 12w Weller SP12, I inherited it along with technique from my grandfather who was a British telecom engineer, the iron is from around the 80-90's and still has the original tip, it along with a combination of technique, additional flux and a solder wire appropriately sized gets everything I solder just right for me - every time...Thanks Granddad!
40-60w is an average range on what allot of irons will be rated at, my other iron is a 25w similar to the Weller, I also have two gas soldering irons for mobile work. The bigger of the gas irons is handy with the tip removed as its basically a mini blow torch and works excellent on heat shrink and those jobs where you need a small flame with a bit more power.
What iron are you using ?
The tip of your iron needs to be "on point" Ravi, the problem comes from oxidation and not keeping your tip clean, once your tip becomes oxidized the solder will no longer want to flow or stick to it properly and this is a problem. Don't clean your tip in flux or water, this shocks the tip and damages the Iron and Chromium plating, just dip the tip in some pure Rosin after each joint and that should be good enough for the tips life time.
Solder to the tip of your iron and then to the area/joint to be soldered, your transferring the solder from one to the other, try and do this with as minimal amount of heat going into your component as you can and your now doing it correctly.
Soldering isn't rocket science Ravi, there are lots of options in terms of tools and technique but a few fundamentals need to be right for it to be successful, if left those balls of solder you've done so far could come lose and as such cause arcing, arcing not only damages components and equipment but it can cause fires too !!!!
Here is a video, the most relevant section about Flux starts at 7 minutes in, the astute of you will identify the difference in working with fresh unoxidized surfaces vs. oxidized surfaces such as those in the job Ravi is undertaking and the correlation in my recommendation of using flux.
I didn't recommend adding Flux to Ravi's game because it sounded good :witless:
https://www.youtube.com/watch?v=vIT4ra6Mo0s
Well, that's not very fair, is it? Did you not read post #53 and #56? That's all there is to it. Like you say, soldering is not rocket science, but needs some practice. He was given a google link but I did not pick any specific video, I think he should do that selection on his own.Quote:
Originally Posted by Lee Roberts
My iron is a 24v 50W Weller from 1978. It still works well. Of course, it does not have the fancy temperature regulator and display, but I never really felt any need for that.
Attachment 22406
I have used up several tips and also have different type, depending on the purpose, I change when necessary. I would not use a high voltage type of iron, which the 12W you have been given is, on any electronics, but I know many people use tools which are not suitable. Anyway, while it may have a nostalgic value for you, I personally would only keep it as a memory.
Regarding flux, I stand by what I have said. It is waste of money. On electronics one should not use any other type of soldering wire than the one with flux in the core of the wire. As a matter of fact, too much flux can also cause problems, so it is not true that using flux can not hurt. Flux fluid is used only in industrial soldering, where the PCB is travelling through a flux foam first and then through the melted soldering wave.
https://youtu.be/VWH58QrprVc
Manual soldering of electronics don't need any flux foam or liquid.
My experience is that if there are balls then it is enough to heat them well up, until completely melted and either suck it up or in many case it will float out because there is normally enough flux around the points. If if does not float out and look like figure A in the picture I provided then there is nothing else to do than suck it out and apply new solder.
Takes a 15 minutes to half an hour practising and that's it. Really very simple.
Lee you have not read this post from the beginning I feel. The questions you have asked have all been answered.Quote:
So far the only advice he's had is to get a solder sucker and start again, clearly there is more going on than that and he needs more experienced input, let's give him that instead shall we.
You are correct, I owe you and anyone I have offended an apology, I did read post #53 but I unintentionally skipped over the paragraph that starts with "...remove every large clump" as I was more attracted to the do's and don'ts picture. I also totally missed post #56 entirely.Quote:
Originally Posted by A_Camera
I'm very sorry to you and anyone else I offended, at the time I felt it was a fair comment to make however I was wrong so I'm sorry about.
I understand.Quote:
Originally Posted by A_Camera
Ok well now you've got your wires crossed because flux is not a waste of money at all, it helps and there is no questioning that. It is used extensively in the repair/rework arena by many and my own real life experience is that it does help with non SMD soldering too, especially when you're dealing with old pcb's. If you've got it handy there is no reason not to use it in my opinion and that is how I solder.Quote:
Originally Posted by A_Camera
I stand by what I said and think it will help Ravi along with his soldering.
No one said it did, however they put it in the solder core for a reason. Exactly, in your experience...Quote:
Originally Posted by A_Camera
Camera, I'm just offering Ravi what I can from my own understanding and experience, earned from actually doing it and experimenting myself. I do not proclaim to be some kind of authority on soldering.
My second post with the video was somewhat meant in jest, I thought that would be apparent when I said "the astute of you will identify", sorry if that post offended you or prompted you to feel the need to explain your own authority/experience, again that wasn't my intention at all, it was just a light hearted joke that also covered the "why use flux" for anyone who wanted it.
Here is a link to Louis Rossmann's YouTube channel, he is one of many that use flux every day, day in day out to get their work done.
His video's will demonstrate what I am trying to explain regarding using flux or not and will have the last word on my behalf, you the reader can decided if or not you would like to try some additional flux in your soldering diet.
Ok thanks I will have another look, will probably leave adding anything else so Ravi can get his build log back on track.Quote:
Originally Posted by Clive S
Thanks and sorry to all :dejection:
I know very well what flux does and when to use it. In fact, the very same demonstration is done in your video, just like I am saying in post #56.Quote:
Originally Posted by Lee Roberts
https://youtu.be/vIT4ra6Mo0s?t=8m1s
He is soldering large surface, so of course use of flux is a good idea. He is soldering to a copper plate with a blow torch from beneath, not a PCB, and what he does is the same as soldering pipes. So of course, use of liquid flux is a good idea, as it is demonstrated at the 7 and 8 minute marks. When soldering PCB manually flux is unnecessary because the solder wire already has enough. More important is HOW to solder and which tools are used. If the tip is too large or too small, or the temperature is too low, or the solder is applied to the tip and brought to the surface and so on...
Quite the opposite to you, if I make a PCB and see that it has a lot of oxide, or old flux or anything greasy on it I use PRF 6-68 to REMOVE flux, oxide and almost any other dirt, and that makes soldering really easy. I also use the same if I buy electronics from eBay and see that the PCB is badly cleaned or not cleaned at all, and is full of sticky flux. I routinely clean all my PCBs after manually soldering because there is always just too much flux rest after manually soldering PCB.
Well I have redone the soldering, and im pretty happy with it. Its still balled up a little but the prongs stick out through the board a fair bit so didnt really have a choice as I wanted the whole of the prong covered in solder, they are very round and meet the metal contact on the board pretty much perfectly, plent of solder also flowed into the connection to begin with :-)
Before
Attachment 22414
After
Attachment 22415
singed the board coating a little but the solder had made a solid connection and like I say plent of solder has flowed into the conection
After you all explained what a star was in the box it was obvious where it was when I opened it up. I have drilled a small hole near the motor connections and linked a bolt to the star so I can attached the earthed wires from the motor cable screens to it
Attachment 22416Attachment 22417Attachment 22418Attachment 22419
also popped to my best mates workshop, he has a few little toys ;-)
Attachment 22420Attachment 22421
Yep looks much better, you can see now how they resemble the other original joints more, nice job.Quote:
Originally Posted by ravihotwok
:) Mates with benefits a :semi-twins:, your plan for the control box and the earthing looks to be ok.Quote:
Originally Posted by ravihotwok
thanks very much lee, still a bit iffy but the main thing is I now know the theory behind it.
Yeah my mate does a lot of contracting to a few aerospace firms and has helped me out a fair bit with advice, nearly pissed himself when I showed him my 4 axis machine lol
Work has been crazy busy at the moment so only been able to do a little bit on the build. I have started to create an enclosure for the machine, this will consist of a sealed unit with 2 led strip light running at the top of the enclosure front to back each side. One side of the enclosure will be perspex and and front will be a hinged perspex door. There will be an extraction system installed on the side opposite the perspex. Its a very make-shift idea but it will serve a purpose I think and help keep the area as clean as possible.
I have replaced all the wood on the workbench from cheap thin mdf to 12mm thick ply wood for stability, weight and strength.
Attachment 22433
Now I have added a few coats of paint to the inside of the enclosure to aid lighting
Attachment 22434Attachment 22435
And here is the side perspex screen installed
Attachment 22436
One other issue I have is that I now have a additional power supply/controller for my 600w spindle which wont fit within my planet control box. I have decided to fabricate another box lid which will fit and attach to the top of the existing planet box. Here is the grp mould I have made so far to achieve this
Attachment 22437Attachment 22438
Nothing really that interesting and still haven't registered the license correctly since changing from the crap control box to the new one so hopefully I will be able to sort this at the weekend and make some progress on finishing the wiring. All in all enjoying the small amounts of time I spend on this so far which is great. More to come :-)
Have you had it cutting yet?
christ no lol
waiting on some more cable track to feed the limit switch cables through, also need to solder the earths onto the motor cables, trying to run the cables as separate as possible hence the additional cable track, once the enclosure is finished I can work out the exact length of the cable so they are as short as possible.
Im not too keen on firing the machine up when its half way through installation as I know I will start making loads of stuff and just make a mess everywhere lol
Spent a few mins last night installing the new LED strip lights inside the enclosure, just need to sort a switch out then they will be fully functional.
Attachment 22449