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Great start, the thing about welding is that it doesn't matter what it looks like as long as it's strong which that looks as tho it is. It can be tarted up later with a grinder or flap disc and it's not easy to get neat welds with mig on thick material unless you have a really powerful machine and then it just pulls out of alignment more.
Mike.
Thanks Mike!
I have a 150Amp welder but I'm not convinced that's what it actually puts out, think it's a rebadged Chinese POS but I was given it free so can't complain. There are so many welds on this thing that I don't intend grinding everything back - life's too short! As long as it holds together I'll be happy, I'm just chuffed to see some progress.
Cheers :beer:
Not strictly true, with the correct setup and a skill full welder then even a cheap welder can give excellent welds on thick material without too much pulling or distorting as you can see on these pictures of machine we made, one is 5mm plate onto 10mm done with a Cheap £150 180A Ebay Mig, the other is this base frame with some long welds on10mm plate.Quote:
Originally Posted by m.i.k.e
You can see the Mig in the pic of the base frame and if you zoom in you can see 10mm pads welded to a 10mm plate, nothing pulled on this frame. Full disclosure here this was My Son Jareds (Jazz) welding, not mine, my eyes are knackered so my welding days are done.!
This said practice makes perfect and a grinder mask's 1000 sins until something falls off...:hysterical:
Attachment 30952 Attachment 30951
...and to the left of the welder, the ubiquitous DeWalt grinder :)Quote:
Originally Posted by JAZZCNC
All seriousness - that's a nice job - surprised that's the result of MIG, approaching TIG quality. Impressive.
I was just trying to keep his chin up, now you have posted them pics up JonnyFive will have an inferiority complex :hysterical:Quote:
Originally Posted by JAZZCNC >> Not strictly true, with the correct setup and a skill full welder then even a cheap welder can give excellent welds on thick material without too much pulling or distorting as you can see on these pictures of machine we made, one is 5mm plate onto 10mm done with a Cheap £150 180A Ebay Mig, the other is this base frame with some long welds on10mm plate.
atb Mike.
Is it a complex if you know you are inferior?
My welding is crap but it's good enough that my machine has stayed pretty accurate and hasn't fallen apart in the few years I've been using it. I just don't show it to people...
But don't forget the angle grinder!
Somehow I don't think JohnyFive is a snowflake so I'm sure he'll be fine....:hysterical:Quote:
Originally Posted by m.i.k.e
But in all seriousness, the point of my post was more to let people know that even a cheap Mig can produce very nice welds even on thick-ish material. Yes, 10mm is pushing the limit of a cheap welder but it can be done.
Yes, the good old Dewalt grinder and it's got the Evil wire brush on it.:devilish:Quote:
Originally Posted by Doddy
If you think that's good you should see the welds that he does with the big German-made EWM Mig welder.!....That thing is amazing and the speed it welds at is unbelievable, the control panel is like a spaceship, you tap in a code for the material and type of weld joint you are doing and it sets all the settings amps. volts, wire feed, etc and monitors them as you weld, you basically pull the torch along and the metal just flows like water, he says it almost feels like cheating because it's so easy.Quote:
Originally Posted by Doddy
My reply is " So it bloody well should @ £6k"....:hysterical:
It takes more than that to upset me [emoji1787] I know my limitations but I’m happy that this thing is strong enough to do its job. The vast majority of the welding I’ve done so far won’t be visible, hopefully I’ll improve a little by the time I get to the bits you’ll see.
I know you shouldn’t blame your tools but tonight I borrowed a friends inverter MIG welder and it seems to produce nicer welds. With only 4 power settings on my welder it always seems that the right level is in between settings. The other welder has infinitely adjustable Voltage and feed speed so it’s easier to get right.
That’s some seriously nice looking welding there Jazz, maybe by the end of this project I’ll be 1/10th as good as that!
Making good progress on the fabrication work [emoji1303]
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Looking good, I'm going to have to get some steel ordered and make a start or that will be another year passed lol. That's going to be one strong machine with that bracing.
atb mike.
There you go, fixed it for you :)Quote:
Originally Posted by m.i.k.e
Yep, strong and heavy - CAD says the fabrication is over 370kg!!!!!Quote:
Originally Posted by m.i.k.e
Sent from my iPhone using Tapatalk
Careful not to get caught up in the "Heavy is good" trap because heavy in the wrong places can be just as bad as underbuilding.?Quote:
Originally Posted by JonnyFive
At least if you are underbuilt you can take lighter cuts and go faster but too heavy and you'll struggle to hit feed rates or suffer from missed steps through motors not being powerful enough to handle the inertia and as we all know it's a lot easier to put weight on and beef up than take it off and a lot cheaper if your too heavy and end up having to replace motors and drives etc.
Understood Jazz. The 370kg is for the welded (static) base frame, I thought mass here would help with damping? The vast majority of the moving bits are aluminium, I haven’t worked out the total mass of the gantry perhaps that’s something I should do?
Yes nice thick tubes etc will certainly help to dampen vibrations and without a doubt, you need to look at the gantry weight and screw sizes you'll be using to help with motor selection, etc. Mass in the gantry certainly helps here as well but this does come at a high cost with motors etc and isn't always needed so it's worth taking the time to work out the weight you'll be moving.Quote:
Originally Posted by JonnyFive
Frame nearly fully welded and ready for paint [emoji41]
This thing is a beast!
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Got the frame as level as possible and poured the epoxy this weekend:
Attachment 31165
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Attachment 31170
Overall I'm very happy with it, there's only one area I can see that has a slight wave to it, think I either cooked it with the blow torch or hit it too late and the epoxy was too solid to smooth itself out. I don't think it will be a problem, I'll see once I get to fitting the rails and fill / shim if required.
Can anyone suggest what size cable chain I’ll need for each axis please? Just about to place an order with BST and was going to add these to the order.
[emoji482]
Anyone got any recommendations on the safest way to pay BST? Direct through Aliexpress or via Paypal?
I've done multiple orders from BST Automation direct through AliExpress.
The few people I have seen online that have had any issue with initial order seem to have had issues sorted fully by BST (Fred)
Fred is 100% trustworthy so pay him any way you are most comfortable or suits you best. I pay him directly through bank transfer and have done for 10+yrs without any issues. (unless I cock it up like I did the last order, but still got sorted by Fred)Quote:
Originally Posted by JonnyFive
Don't forget to mention MYCNCUK when you speak to him, he likes to look after members if he knows you've come from here ;-)
Last time I used Aliexpress they used an intermediate holding area (escrow?) for my payment and it was only released to the seller when I received it. I’m pretty happy with that. Also if it is Fred then no problems.
Is it normal to have to pay import duty to the delivery courier? I’ve had 2 packages from China, from 2 different suppliers - one from BST was delivered no problem, the second with my motors the delivery guy said I have to pay import duty. Just wondering whether I got lucky on the first one or I’m being shafted by the second?
Entirely normal, if the cost is over £135.Quote:
Originally Posted by JonnyFive
Under £135, the seller should be VAT registered, and collect the VAT on the UKs (and I think it's also came in for the EU) behalf. If you paid through an online marketplace (aka eBay, Aliexpress), then they have to do the VAT collection.
As for the one you didn't have to pay, give it a month. Some couriers deliver, then send you the bill. Others bill you before they'll deliver.
You might have been lucky. I know I've never been billed for some orders in the past, but generally higher value stuff doesn't slip through the HMRC net.
Good to know, thank you!! I’ll brace myself for the upcoming bill on the BST delivery [emoji33]Quote:
Originally Posted by m_c
I’ve pretty much got all my hardware now(gantry extrusion, bearings, ballscrews, motors & drives etc), all I need is the machined parts to be able to start assembly - just waiting on my induction at the local maker space so I can start work on the missing pieces [emoji41]
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My mind is starting to think about the electronics, this is where my knowledge falls down big time!! I’m not sure where to start really. I think Ethernet is the way to go, I’m thinking UCCNC. I have closed loop stepper motors (not sure did that makes a difference?). Apart from that I’m snookered. Can anyone point me in the right direction please?
[emoji482]
Whilst progress is slow on machining all the parts I need I have put together my attempt at the contrrol circuitry. I have to give a massive shout out to both ROUTERCNC & Joe Harris for their superb videos and documentation covering this side of things - I've watched / read it all several times!!! Using their content, some intense Googling and reading of manuals this is what I've come up with:
Attachment 31390
Attachment 31391
I do have a number of questions, hopefully someone will be able to help:
- Is a mains filter required for the VFD? I notie=ced ROUTERCNC used one but Joe didn't
- I'm assuing I don't need to connect up REV on the VFD as I'll only be running the spindle in one direction?
- I've seen diffferent ways of connecting up the step & direction pins from the motor drivers - either commoning up the +ves or the -ves - what's the difference? Is it to do with picking up the leading or trailing edge of the signal? Which should I use? I'm using closed loop steppers if it makes a difference.
- My motors came with long cables with extensions - are they ok to use? Or should I be making up my own screened cables?
- Do I need to run an earth wire to the gantry & frame?
- Is the rotary interlock switch necessary?
- Do I need to connect the spindle pin 4 to earth? I've read contradictory things about this.
- Do I need to connect the ENA+ & ENA-?
- Do I need to twist the PUL & DIR wires?
- Is it acceptable practice to crimp 2 wires into one ferrule? Or put 2 ferrules into a single terminal?
- Should all the 24V feeds going to the AXBB-E controller be from the switched 24V or permanent supply?
I'm sure there will be many more questions to come. Any feedback would be much appreciated.
Cheers :beer:
1. The filter is more to protect the supply (and other devices) than the VFD.... they're noisy buggers.
2, Correct
3. Closed-loop makes no difference. Whether you're driving high or low is largely irrelevant (the two pins are the anode/cathode of an internal LED used for isolation - so switching either works). What this gives you though is flexibility - for example an open-collector (open drain) drive is designed for low-side switching (i.e. take the + to supply, and switch on the -). The axbb manual describes the non-isolated outputs as being able to push/pull 20mA - so can source (+ve) or sink (-ve) - so can drive either input.
4. Your call. It's better to cut to length but not if you risk damaging anything.
5. Yes. Unequivocally. Do I?, I might.
6. I only glanced at your schematic - it feels a safe design but more than I'd do for a personal machine. I can't knock safe design but I can duck an errant shock 50% of the time.
7. It's a good idea. Otherwise a stray wire in the spindle could short to the enclosure and zap you. Of course your protective earth will then ensure that you brick your VFD before your blow the protective devices.
8. No. Unconnected, the LED opto-isolator remains inert and the drivers enabled.
9. It's a good idea, but realistically will achieve little. You'll be generating pulses at maybe 100kHz at around 5mA, that will generate some EMF but I'd hazard a guess that you're not going to impact much. The driver inputs going through an opto isolator will be pretty tolerant of any induced emf.
10. Yes, in fact I have insulated ferrules that accept two cores (i.e. a wide rectangular receptacle rather than round), Use common sense - if the cores fit comfortably then there's nothing wrong. Test each crimp.
11. I'd go for the permanent supply, otherwise you can end up with pull-lows on outputs when you don't intend this (remember, you still have a 0V supply to the AXBB, it's capable of hard-driving low). But remember I've not really looked at your schematic.
Thanks Doddy, appreciate the feedback.
I see, so it's to protect things upstream of the VFD on the same mains circuit?Quote:
Originally Posted by Doddy
:thumsup:Quote:
Originally Posted by Doddy
Thanks for the explaination, I'll leave them as they are.Quote:
Originally Posted by Doddy
I'm fine with cutting them to length.Quote:
Originally Posted by Doddy
I'll add one in.Quote:
Originally Posted by Doddy
I'm still in 2 minds, it looks cool but isn't really doing anything that the switch on the mains socket doesn't do other than stop you going in the cabinet which I wouldn't do.Quote:
Originally Posted by Doddy
Easily solved, I can add it. I've also seen people saying you need to open up the spindle and check that pin 4 is actually connected to the spindle body, I'll check this too.Quote:
Originally Posted by Doddy
:thumsup:Quote:
Originally Posted by Doddy
I'll do it anyway.Quote:
Originally Posted by Doddy
:thumsup:Quote:
Originally Posted by Doddy
I don't fully understand what you've said but will swap to the permanent 24V supply - sounds like it's the way to go.Quote:
Originally Posted by Doddy
You could probably check this with a multi meter rather than take it apart and brake any seals etc...Quote:
Originally Posted by JonnyFive
#4 Depends on the quality of the wire, the wire on the Lichuan motors we use isn't shielded and we never have any noise issues from it, only on very long wire runs ie: 8x4 or 10x5 machines do I tend to fit shielded cable but even then it's only precautionary thing and I doubt would have trouble based off the other machines we built.
#7 We don't connect this as it's given me problems in the past with noise, if the chassis/gantry is earthed then you won't have any issues.
#11 Permanent 24v and 5V supply otherwise you'll drop power to the Axbb-e and lose your Workoffset if you haven't saved it first, UCCNC only saves the Workoffset on shut down so if you haven't saved the offset then it will be lost with a power cut. It's also a pain in the arse having to restart UCCNC, reload the G-code etc just for an E-stop.
Thanks Lee. I have done a continuity test and can confirm pin 4 is connected to the spindle housing.Quote:
Originally Posted by Lee Roberts
Cheers
I'm assuming this is something I could easily upgrade if the need arises once I'm up and running? The cables I have came with 3m extension cables, hopefully these will be long enough.Quote:
Originally Posted by JAZZCNC
OK, I'll leave it un-connected. The cable from the VFD to the spindle needs to be shielded but with the shielding only connected at the VFD end and not to the spindle connector - is this correct?Quote:
Originally Posted by JAZZCNC
I'm referring to the 24V to the isolated inputs, the 24V and 5V power connections to the AXBB-E are permanently connected. Should the isolated inputs be permanent too?Quote:
Originally Posted by JAZZCNC
Cheers
Yea and do the same with the control/comms wire to/from the vfd, except connect that earth to your main star ground in/at the cabinet end.Quote:
Originally Posted by JonnyFive
No ground loops etc...
You mean the wires going to DCM / FOR / ACM / VI on the VFD?Quote:
Originally Posted by Lee Roberts
No, sorry I meant to say shielding not earth, but yes the shielding for that group of wires, not the connections themselves...Quote:
Originally Posted by JonnyFive
So I'm talking about the control wire you would also install so that the main cnc controller can control your VFD from software.
Also, I think you should choose Doddy's advice and mine on this one and definitely connect Pin 4, it costs nothing to do and I too would rather sleep well at night knowing your/my spindle housing is properly wired to be safe in a fault condition.
Earth/ground is there for safty first and should be used as intended, using it for noise drain should be considered as a secondary bonus feature in this application in my opinion.
Noise issues can be isolated and remedied, restarting your heart isn't as easy to do...
I have updated the schematic:
- Earth wire from VFD to pin 4 on spindle added.
- VFD to spindle cable screened with screen attached to ground.
- DCM / FOR / ACM / VI wires all screened and earthed.
- Isolated inputs connected to permanent 24V.
Attachment 31542
Finally a bit of progress to report. It's taken way longer than I'd hoped to make up some of the aluminium plates for the gantry mounting but did the first fit up last night and I'm happy with how it looks:
Attachment 31807
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Without having a definitive datum to work from this is how I set my first linear rail:
Attachment 31812
Is there a better method for ensuring the rail is straight?
:beer: