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How big are the bolts for the rails? Will they fit in the profile that you've drawn? As Jazz says the profile is looking a bit small and weak, you could do with beefing them up a bit. It's looking like you're putting the Y axis ball screw on the front of the gantry, you'd be better putting it on the back and bringing your spindle nearer the front of the Y axis otherwise it could be quite a way off the front and a way in front of the X axis bearings. Are all the rails the same size?
What Dean is saying is you have very small clearance from gantry to bed. You need sth like 230mm distance for a 200mm Z axis travel, if well designed. Do you have that space as drawn?
I'm adjusting to lower Z depth, around 80mm would be ok for me
can't I just reduce the space I reserved at back of gantry from 80mm to 40mm? so that the plates and spindle come within the bearing rangeQuote:
Originally Posted by njhussey
Hey everyone, I'm in the process of redesigning the gantry and need your input, I will probably need to use pulley and belt for both Y and Z based on the new placement of motors.
can you please help me in figuring out the belt length I require based on distance between motor and ballscrew? I prefer 1:1 ratio and based on what was recommended to me I think HTD pulley 5mm pitch 15mm width is good?
many thanks, will try to post design photos soon
Here is the belt length calculator , sorry, busy now but later will take a look if nobody does beforeQuote:
Originally Posted by Noplace
http://www.product-config.net/catalo...an/config.html
thank you very much!
Just a preview render, if you have comments please let me know.
Based on center distance I got around 292.2mm belt length, but in the site it says next available length is 295mm , i assume that is a standard length increment across all vendors, so is it ok to get that length ?
http://www.mycncuk.com/attachment.ph...id=15114&stc=1
You will need to put slots in the motor mounting to enable you to have adjustment to tighten the belt. It is quite normal to have 30 - 40 mm adjustment. >clive
The slots need to be 1mm wider than the OD of the motor mount hole. Some servo motors will not allow that movement because the center part is bigger than nema 23 for example, but i can assure you that even 5 mm possibility to move is ok if you use that calculator. Just tested that theory with my servo motor mounts where it was not possible more play. So on a Nema 23 +-10mm both side from center hole is more than enough. Care should be taken if the mount is milled deep into a plate and the motor needs more play just to pass through and enter at its spot.Quote:
Originally Posted by Clive S
The reasoning behind the 30mm is to allow for the possibility to change the pulley ratio if needed. ..CliveQuote:
Originally Posted by silyavski
And excellent reasoning dear Sir. . :applause:Quote:
Originally Posted by Clive S
I think what silyavski is saying is that the centre hole on a nema 23 needs to be about 40mm dia to clear the 38mm raised boss on the end of the motor. If you cut long slots for the motor mounting then as these are about 47mm apart and about 6mm across then they get very close/ too close to the centre hole. On a servo motor this overlap sound like it is worse (don't own servos myself)
If you need a long adjustment slot (more than +- 10mm) a workaround could be to lightly pocket the 40mm centre clearance instead of a complete cut out ? Away from computer so can't check this for sure. Is there another way?
The centre hole on a Nema 23 gets awful close......well actually this close:
Attachment 15115
It's actually thinner on mine now than shown in the picture as I tapped the stepper flanges M5 and machined the slots 5.5mm instead of 4.5mm.....
http://tapatalk.imageshack.com/v2/15...c43aba6d23.jpg
Quote:
Originally Posted by routercnc
Exactly thats what i meant. Thanks!
There must be many ways to do a thing but here is how i think:
-more or less center to center around 90mm, so that usually the belt is in the region of 270 to 315mm depending on the ratio.
-Dont have the time now to play and prove it but at that distance/look at the Nema 23 mount/ was possible to lower the small pulley teeth count and rise the other , so as i remember 1:1 to 1:2 was possible may be even more, without changing anything. I just remember that when doing the yellow machine there was that consideration also.
Same with the servo machine now i am building but not to such extend, due to shorter play possibility.
Below you will see a picture with the maximum movement according to me and having in mind the parts were laser cut from steel. So maybe from aluminum could be more play.
Nothing to prove with all that , just sharing for your consideration and if possible to help avoiding errors. Thanks
PS. The measures are radiuses, possible play and size of the thinnest part there
http://www.mycncuk.com/attachment.ph...id=15121&stc=1
Neil It is close but it works OK of course you can put washers on the cap heads to spread the load.
Silyavski Another way would be to mount the motor on to a plate with no adjustments and then mount that plate with slots on top of another plate so that the motor and its plate would be adjustable. ..Clive
Nema 23 Boss is 38mm-/+0.1 the whole point of the boss is to have close fit to stop movement so making 40mm hole is wrong way to go aout it. 38.3mm usually is just enough for nice snug fit. When done this way then there's no problem with slots or mounting holes if again they are milled to correct size also.!
IF you don't have room for slot adjustment then use an idler gear to take tension up. Not ideal way to do it but will get the job done.
I will do Clive, just mounted it at the moment to check it can tension OK and that I'd got the belt length correct before dissassembling for wiring and final re-assembly.Quote:
Originally Posted by Clive S
The Nema 23 boss is 1.5" - so 38.1mm. It's there to allow the motor to be mounted concentrically to another shaft by machining the mount to be a close fit on the 38.1mm diameter. In the case here, there is nothing to align concentric to, so all that is required is a cutout of enough to allow the boss to fit. There's often a +-0.05mm tolerance on the boss diameter, so in the past I've machined the cutouts to 38.2mm to be on the safe side. You don't want it tight else it will be harder to tension the belt. Also the cutout for the boss needn't go all the way through the material - 2mm deep would be plenty. e.g:
http://www.mycncuk.com/attachment.ph...id=15122&stc=1http://www.mycncuk.com/attachment.ph...id=15123&stc=1
thanks guys for all the info, one question on another topic: how do you mount the linear rails on steel boxes/frames ?
I'm thinking of designing the body out of that since its readily available locally instead of alu t-slot extrusions but I don't know the technique you use to mount them, seems you cant access under to put nuts for the bolts!
If the steel box section is 5mm thick or so then you can drill and tap it and bolt the rails directly. You can optionally place a strip of steel inside the section clamped to the underside of the top surface and drill and tap through both to get better thread engagement.
Be aware that your rails will only be as flat and planar as the top surface of the box section so read up on epoxy mounting or shimming methods to get the best DIY result.
Thanks for the great info, I would like to try epoxy but I have no experience and I'm afraid it just might be messy and don't think local workshops here have experience in doing it. would shimming be more approachable and any guides on that?
on a different topic I got my VFD (spindle still in the way) and would appreciate if you could confirm wiring:
this is a FC300-2.2KW
http://www.mycncuk.com/attachment.ph...id=15196&stc=1http://www.mycncuk.com/attachment.ph...id=15197&stc=1 http://www.mycncuk.com/attachment.ph...id=15198&stc=1
So L and N are input obviously, PE is ground, PB P+ are braking resistor connection.
first do I connect PE to both spindle and input ground or just input ground? I'm assuming spindle comes with 4 inputs so 3 of them would be the U V W and last one is earth, is that correct?
second, I have this board called C6 http://www.cnc4pc.com/Store/osc/prod...products_id=58 which is supposed to control the speed and on and off/dir from the software(mach3) once I connect it to my BOB.
would you be kind to confirm the connections between the board and the VFD? the only one I figured is analog output to AVI.
the board has separate ground for the analog and digital, should they be both connected to the COM inputs in the VFD? and there are two COMs which is confusing me further.
Generally you will need the C41 board not the C6 for spindle control. why did you do that?
c41
Inputs a PWM and outputs an analog 0-10VDC.
C6
• Inputs a frequency (step) and outputs an analog 0-10VDC.
Read the manuals how to connect them:
http://cnc4pc.com/Tech_Docs/C6R6%20and%20Huanyang.pdf
as an answer to your question from the manual:
Make sure the grounds of the analog circuit are keep
isolated from the logic (+5vdc). Use a multimeter to confirm there is no
continuity between the two grounds before applying power.
Dont be in a rush. :toot:
I'll be using the C6 with C35 from same site, I checked with their support and they confirmed that they work together so I assume it would work and mach3 could output the required frequency(step) signal, did I miss something? please enlighten me :D
Quote:
Originally Posted by Noplace
Yes they will work fine. The difference is that with a Step based spindle control you use or lose an Axis output. With PWM then you don't.
This NOT a Huanyang Vfd.!! The setup is similar but the connection terminals are different names and it's not wise to presume just because they are similair labeled they actual do the same as Huanyang or any other Vfd.Quote:
Originally Posted by silyavski
Also looking at the table for VFD you provided the Analog and Digital input Logic (which is 24V not 5v) share the Same ground so maybe can't use this board.? Check with a meter to be sure but normally Analog as it's own isolated common.!
Edit: Also the Spindle 99.9% probably won't have a Ground wire. It may have 4 connections but one won't be used. Again use meter to find one that isn't which is often pin4 (look close they will have numbers)
Regards using the PE: Then take the cable shielding at the VFd end back to PE connection. Leave spindle end shield unconnected.
Some people use the 4th connection in spindle to Ground the spindle but I find it's not required if machine frame is grounded.
Hi, it was early in the morning so did not have time to write much. Like Dean said, the board will work but you loose axis.
I have no faith of China so i do the same, check all with meter. Especially the ground.
I always use contact from the VFD on the Estop chain so all stops if motor digs in material and VFD trips or if there is a trip for any other reason.Seems Y1B and Y1C in your case, check manual further.
Here is the full manual for the VFD:
https://drive.google.com/open?id=0B8...UlV&authuser=0
if anyone has time I would appreciate you checking it.
from what I understand:
there are function pins (X1-X8) that can be programmed for multiple functions but default is shown in the diagram showing:
X1 - forwrad start
X2 - reverse start
X3 - stop
so if I can get the right way to hook into these I think it will work.
but also in the manual it states we have to change some default settings to allow controlling start/stop and frequency from outside.
but what I don't understand in general is the need for relays, maybe someone with electronics experience can explain it, isn't it possible to just hook the pins coming from BOB to the inverter input ? unless the relays give a higher voltage?
I understand how relays work (a bit lol) but was wondering how they are functioning in the C6 ( are they outputting 12v being controlled by 5v) ?
anyways thanks for reading and hope someone is bored enough to open the manual and read through! haha
Ok well the need for a relay is to act as the switch.
The vfd will provide 24V source which you take to which ever input you want to use. The relay acts as a switch and keeps the digital input using the same potential as the source.
If you use an external voltage it won't be at the same potential.!!!!! . . . . Hey what the hell is the Potential he's asking him self.? :cower:
Basicly it's ground and all it means is the digital input needs to use the same ground as the source voltage. (Or often other way around and Digital input provides 24V which returns to Com ground)
Either way there must be a path back to ground for the cicuit to be made.
Relays: Well from your statement then I don't think you do fully understand how a relay works.? A relay is just a electro mechanical switch and doesn't output any voltage.
The coils of the relay are controlled by voltage you or the device controling the relay apply. The Contacts of the relay are the switches which open or close depending on type. NC or NO.
In the case of the C6 board the Coils are controlled thru the BOB using "M" commands in g-code. The contacts you just use to make or break a circuit.
IE: M3 would turn on the relay coils closing the NO contact which you run the wire from 24V source on VFD thru one side of contact and back out the other to Digital input on VFD.
thanks that's a good explanation, I had a vague idea of relays but forgot since its been a long time I read about them.
still I'm not 100% clear on it. the relay will be my switch to turn on/off connection between VFD ports. relay has 3 pins : NC/NO/VLIN
-connect 24v to VLIN ?
-connect X1 to NC ?
or
-connect COMM to VLIN
-connect X1 TO NO
or
-connect 24v,comm,X1 to NC,NO,VLIN
sorry for sounding stupid but I need to be sure and understand correctly.
Vendor sent me this to assist also, seems the frequency control is DC so not sure if I can use my board :(
http://www.mycncuk.com/attachment.ph...id=15224&stc=1
Hi,
:toot:Don't make it more complicated than it is. And RTFM:toot:. Read the manual i mean :thumsup: Ok i read it for you so:
What you need to make all work in real life and what you would actually use are exactly 6 things:
1. connect the 3 wire cable to the VFD to power it - 2 x 230v AC wires to L and N to power the VFD and connect ground wire to PE
2. connect U V W to the spindle and the shielding of the cable to the spindle ground or body.
3. connect one of your BOB relay outputs to X1 and Com. When the relay is closed by Mach3 the spindle will start
4. connect via 2 wire the 10VDC output from the C6 board to the VFD, where +10v goes to AVI and ground to COM on the VFD. Thats the spindle speed control
5. optional: split the estop wire and connect both sides to the Y1B and Y1C, so when the VFD is powered all will be ok and the continuity normally closed, if the VFD trips due to bit dig in material or whatever the contact will open and CNC will Estop.
6. program the VFD:
assuming you have bought 2.2kw water cooled spindle you must leave all default and change only the following:
P002 just check if its right for the motor you have bought, 220V default value
P003 400
these 2 are not clear to me. Normally on other inverters its the only place to say the motor accelerates and decelerates for 10 seconds. But in the manual i saw other place also. So - program them as bellow and if the motor continues to accelerate after 10sec and is not completely stopped after command for 10 seconds, then clean them both to 0
P013 10 and remember at mach3 to make for 10 seconds spindle start and stop delay at the spindle screen
P014 10
P021 400
P025 0 this when you have successfully control the start run and speed via mach3. You wont need more to touch the VFD for any reason after that
P064 1 again-you don't need to touch the VFD once all is working, all can,should and i would say: for the sake of not forgetting something - must be done via Mach3 Do yourself a favor and buy a good screen like MachStdMill
P065 1 same what i said above
P067 0 believe me on this, you don't need reversal . the only thing that could happen is you make a mistake and break expensive bit, have been there, done that
PS. Thats it, its not so difficult. Check again what i say for any mistakes and be happy chappy
PS2. Yes, my VFD has connected PE ground both to the ground of cable that powers the VFD and both to the spindle cable and hence the spindle ground. Difference is that i have the separate ground connections on the VFD to do that / Mitsubishi brand/ So i believe both ways is ok. Even if you don't connect Spindle ground to VFD ground it will work, but remember to properly ground the machine itself
Yes it will work fine the C6 board is putting out a DC signal.
Ok well this is a different diagram which looks like the Analog com is isolated from input logic and will work. It also resembles the terminals on the actual VFD.
So in this case you are ok and the C35 board will work. Wire it like below.
Attachment 15225
Man you guys are awesome! thanks a million silyavski for the details. and Jazz for the confirmed diagram!
now just waiting for the Spindle shipment to try it out!
When the spindle starts for the first time make sure it is rotating in the correct direction if not reverse two of the phases ie swap U and V or U and W that will reverse the direction. ..CliveQuote:
connect U V W to the spindle
Heya everyone, I've been shy of posting any updates since last time because I'm afraid of all the judgement I will receive from you hehe. Mostly because it has been a rough half year of finding a good workshop to machine all my plans, unfortunately in my country the quality of workshops is pretty low compared to you guys. and I am no machinist so I don't have the skills nor the equipment to do it by myself. (but hopefully in the future)
So I hope whenever I post something please don't judge anything that is not square or straight or doesn't look machined well as my goal was to get this thing running and be able to cut even if not perfect the amount of knowledge and skill I have acquired from building this is a ton.
But of course any tips and constructive criticism is appreciated!
of course lots of knowledge and wisdom was gained from the posts of people in this forum. my plans was based on your comments plus other machines designs which were posted here. again its not the best but I think I'm satisfied with what I came up with.
It's not complete but almost all parts will be ready this week and I will start assembling everything.
I had a issue with shipping my spindle because china post takes forever to reach my country so the supplier shipped me another one which hopefully be received this week. ( I think the original shipment got lost, or maybe I'll receive it after a year! heh )
the first thing I did when I started is build the electronics panel so I have tested it before and got it all working, the only thing left is to test the VFD with the spindle and hopefully make it controlled via mach3 with the generous instructions from the above posters.
so for now a small update, here is a video of my x-axis one side testing with a drill. I have switched the frame from Alu T-Slots to steel square sections, it came out decent but might need adjustment :hysterical::hysterical:
https://youtu.be/zZthFVKWcD0
Well it seems to be coming along nicely don't be worried about any judgement as it is generally meant well to help you along the way.
If it was me I would drive the screws through belts with a 1:2 reduction as that might help with resonance etc. Keep up the good work. ..Clive
Don't be afraid your doing a very nice job and we have seen much much much worse.! :applouse:Quote:
Originally Posted by Noplace
I like driving through belts because it saves trying to line things up. However if you simply bolt the motor to then end of the screw and do not care how much it wobbles and twists, all you have to do is stop it turning and you can have a much better connection than you could possibly get through an expensive coupling :D
Thanks guys will consider the suggestions.
now all i have remaining to machine is the motor plates, any advise on the designs ? the motor screw holes are not in correct position so please ignore that.
http://www.mycncuk.com/attachment.ph...id=15661&stc=1http://www.mycncuk.com/attachment.ph...id=15662&stc=1
Looking really good, well done.
Be aware that if you turn a stepper using a drill it will generate power (like an alternator or generator). If it is connected to the stepper driver board this can be a bad idea!
For motor mounting plates you need to have slots not holes so you can tension the belt. 20mm or so slot is a good start but you'll need to decide based on the standard belt lengths available and making sure you can tension it. There are some online belt length calculators available so make sure you use those and place the centre of the slot in the nominal position.
The motor plates are usually pocketed with the motor set into the plate allowing the drive belt to run free over the top surface. You've got the motor sitting flush with the rear surface so you are having to cut all the material away in the middle to allow the belt to run. Not saying your way won't work but its usually done the other way to keep some strength in the bracket.