My first CNC machine finally turned up just before xmas and I've been anxiously trying to get the table/enclosure ready for it so I can start to use it finally!
The table is near enough finished so I now turn my attention on to the upgrades required to make the first cuts as painless as possible. (without breaking the bank too much)
Looking at what I have got..
- 3 of 57HD5401-14S/8 Stepper Motor - 1.8 step angle. 3A N1508
- A blue controller box with an all in one controller/driver board.. JP 3163B (Same as this one)
- A 24V 8.3A switching supply
- A 1.5kW VFD for the water cooled 800W spindle.
- This 35W 24V diaphragm pump
As I understand from a similar machine thread here, the PSU and drivers aren't up to the task of running the motors.. As such I'm considering going with three planet cnc driver boards - the 6A 50V capable one.. http://www.planet-cnc.com/files/MotorDriver60A-256.pdf
Which brings me to the first question..
1) Is this driver reasonable for my needs? (Mostly cutting prototypes using thin (less than 3mm) aluminium)
2) Would you buy better motors at this stage or are mine ok? (coupled with beefier drivers & a higher voltage PSU)
PSU wise, I'll probably either build something or buy their 48V PSU.. not decided yet..
Cables.. as I need longer cables.. about 3 or 4 meters length, it's just as easy to rewire it all with shielded cable so I'm planning to do that..
3) Are my cable choices ok..?
4 core screened CY 0.75mm^2 http://cpc.farnell.com/1/1/196553--c...m-grey-1m.html
Or 1mm^2 http://cpc.farnell.com/1/1/210633--c...m-grey-1m.html
4) I'm planning on adding 5 limit & 3 home switches. I've got some inductive proximity NPN NO coming which I'm planning for homing.. For limit switches.. I'm not 100% sure yet.. any tips?
Am I right in thinking that the switch isn't so important.. so could be a simple switch like this..
Not entirely sure the best way to go with regards to wiring them with the controller inputs available to me... (probably the planet cnc mk 3 - pdf manual here: http://www.zappautomation.co.uk/prod...ownload?id=168 )
Any tips greatly appreciated !
Last edited by d4cnc; 30-12-2015 at 08:47 PM.
In regards to question 1:
Having done a little more reading about drivers... I'm not sure the PlanetCNC drivers are right being only 50V max.. Am I right in thinking 80V drivers would be better?
If so, I'm either thinking DQ860MA (£135 for 3 from Germany)
Or the AM882 (Around same price but from China)
The question is if I can wait a little longer for the China ones..
If it's worth the upgrade, then I'll do it, but if not, then I'd rather not.. anxious to get cutting!
Last edited by d4cnc; 31-12-2015 at 03:12 PM.
Why do you feel the need to upgrade.? If the machine is working then use it. When it breaks fix it.
Regards the Drives then you don't need 80v drives for machine this size. If your thinking to re-use for another machine then ok but for this machine then 50V drives and 44V PSU will be plenty good enough.
If you really do feel the need to upgrade the electrics then go with AM882.
I recently got a 6040 as a size upgrade from a Proxxon MF70. I replaced the drivers with a Gecko 540 and used shielded cable. The pump seemed electrically noisy so I'm using the pump from my laser. I'm happy so far.
I'd say you should start using it and upgrade as you need to. Even the shoddy stepper drivers might be OK for a bit. You may well find that's the only bit that really needs replacing.
Hi, I've not actually turned it on yet, so am just going on what I've heard others say about the electronics not being up to scratch on it.. for example, motors stalling easily, missed steps etc..
So my thinking was, as it's my first experience of CNCing, to just get hold of whatever I need to make sure there's not too many problems ahead of my first use..
So perhaps I'll just get the shielded CY 1mm≤ cable (as it's too short at the moment to reach the control box and VFD, and then power up and use it and take it from there!
(Fred.. what made you upgrade the drivers in your machine?)
The electronics (stepper drivers and unshielded wiring mainly) are substandard, but you know... just have a play.
You may get missed steps but if you don't leave it unattended the worst you'll get is some wasted material. Best start with cheap wood anyway, so no big deal.
I had a Gecko already that I spotted cheap on eBay. Plenty of other good options out there though. My machine was secondhand and definitely missing steps. I might upgrade to a 48v supply but the 24v seems OK for now.
If you need any 2 and 4 core shielded cable for the steppers and limit switches let me know. I ended up buying 100ft reels of both as I couldn't find reasonable stuff in shorter lengths. I'm also using 3 core 1mm Belden CF for the spindle and that seems fine.
Thanks Fred.. and thanks for the kind offer.. I just purchased some from CPC earlier actually as I needed to order some stuff from them anyway..
Assuming that it's ok to fit... it's 7mm outer diameter rather than the 6mm that's in there at the moment...
Have fun. My final tip - don't spend ages threading cables through the cable chain only to find each piece clips open on the inside.
Anyway, it's New Year's Eve. There's a glass of vodka that's calling me.
Last edited by Fred; 31-12-2015 at 11:06 PM.
Hi, I'm looking into the possibility of adding home switches and limit switches currently, and am a little unsure on the best route to take with the standard electronics it came with..
There's a terminal block that appears to be for limits & it's where the emergency stop came connected at the moment.. as a normally open.. with a connection to ground when activated.
Am I right in thinking I can do the following? (Using simple micro switches as limits, and inductive switches as homing.)
PS Fred.. I don't see anyway to open up the cable chain I have.. The only way is to break them apart to make things a little easier I think.. unless I'm looking at it right..
Adding the limits to the e-stop circuit would work as drawn - however, it's a bit unusual for them to have configured it to be normally open. It's a bit safer to be normally closed when running in case a wire breaks etc. and it doesn't work when you press the e-stop.
Adding proximity sensors for the homes is fine but be aware they have 3 wires and run off 10-30V, so they wouldn't be drawn quite as you have drawn them. They also send out 10-30V as a signal so check the board can take this as an input as it could be 5V max.
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