Building My First CNC Router, Looking for Advice & Other Info

[AlexDoran]

Hi Clive,

Thanks for the PSU link, says they are out of stock but i can look for a similar item based on that.

Sorry for my lack of education, what do i need to look out for when it comes to the VFD? What differentiates between the correct & incorrect one?

I am not sure about the independent homing, i will need to check that for sure, is this common practise for machines with multiple screws on one axis? Is this to ensure they stay parallel? I believe it can handle full GCode list, need to research canned cycles, apparently it can handle any file size because it reads from the USB stick as it goes.

Unconvinced with my result from the Centre of Mass evaluation i done, i got on the phone to Solidsolutions, who provide our solidworks license and also provide support, indeed i had done it incorrectly. Here is where the actual centre of mass is on the gantry. It's hard to see, but where it says "Point 1".



Not sure how much of a problem this poses, are the carriages likely to be affected by this? Not how i might remedy this other than reducing the Gantry to a single 40x40 extrusion as opposed to 40x80 and then centralising over the Gantry Base Plates further. This in turn might affect how rigid the gantry is surely?

Thanks

Alex

[RobC]

VFD's are rated for certain motors. So you might have a 2.2kw motor rating and such you will require either a 2.2kw VFD or higher but it's best to use the same rating. Now what I've been having issues with it my VFD has been nuisance tripping my RCD and thus now having a none RCD circuit wired in to my workshop to stop it due to the current load on startup. Also, go for a water cooled spindle, your ears will thank-you afterwards!

Rob

[AlexDoran]

Hi RobC,

Ahh i see, that makes perfect sense, i just didnt know if there were different types that affected compatibility with other hardware. I have asked the seller a question about how many bearings it has. One thing i am curious about, and that i have done no research on, so am lazily asking you guys. The VFD's do you set their speed manually? On our CMS Machines at work we set all of the within the CAM program, its not a problem if this speed is set manually i was just curious.

Thanks

Alex

[Clive S]

The VFD's do you set their speed manually?

You can do either but you have to change the parameters in the vfd I personally have fitted a 10K pot of the front of the vfd, this is very easy and the hole is already there. see this link http://www.mycncuk.com/threads/7388-...hlight=fitting

[AlexDoran]

Hi Clive,

Thanks again mate, ok so the one i linked to originally should be good to go as long as they reply to my question about the number of bearings.

Just wondering now about the weight distribution on the gantry before i start ordering bits.

Thanks Again

Alex

[Clive S]

Sorry for my lack of education, what do i need to look out for when it comes to the VFD? What differentiates between the correct & incorrect one?

Ok look at this link it shows the difference in the types of the standard vfd. LOOK at the front of them that is the best way to tell they have a different layout you want the Huanyang inverter

http://www.ebay.co.uk/itm/TOP-2-2KW-...EAAOSwHnFVvvsm

[Clive S]

I am not sure about the independent homing, i will need to check that for sure, is this common practise for machines with multiple screws on one axis? Is this to ensure they stay parallel

If you are using two screws and two motors you will have to use two home switches to make sure the gantry is put square every time you home.

You can of course use two screws with one motor and a belt driving both screws then one home switch will be fine.

The choice is yours as there are pro's and con's and much debate between the two types.

[AlexDoran]

Ok, i need to do some serious research to see if that controller can handle that, i know it provides for 4 Axis but im not sure if the 4th can be setup as Dual Axis.

So i know i keep banging on about the weight distribution of the Gantry, but i really am being stupid today. It seems at some point i had lost all of the material properties for my assembly parts, ive just spent a little while going through and properly setting the weights of each component, i have based the Aluminium Plates on being a 6061 Alloy, whether or not this will be the material the plates are cut from i dont know, but it was the most common material so i though i would go with that, i re rain the analysis and it has given me a hopefully accurate Centre of Mass for the gantry, indicated by the Red Dot, im hoping this is a pretty acceptable balance and wont cause any undue wear or stress to the linear bearings:



Thanks

Alex

[Nr1madman]

Ok, i need to do some serious research to see if that controller can handle that, i know it provides for 4 Axis but im not sure if the 4th can be setup as Dual Axis.

So i know i keep banging on about the weight distribution of the Gantry, but i really am being stupid today. It seems at some point i had lost all of the material properties for my assembly parts, ive just spent a little while going through and properly setting the weights of each component, i have based the Aluminium Plates on being a 6061 Alloy, whether or not this will be the material the plates are cut from i dont know, but it was the most common material so i though i would go with that, i re rain the analysis and it has given me a hopefully accurate Centre of Mass for the gantry, indicated by the Red Dot, im hoping this is a pretty acceptable balance and wont cause any undue wear or stress to the linear bearings:



Thanks

Alex

I'm sorry to inform you that the fourth axis on the controller is only rotational and can't be slaved. Have been drooling over it myself but have to go another way as I'm using 2 motors for my X axis. Boyan runs it with two drivers on the same signal but because of that he lost the ability to home separately.

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[Desertboy]

Hi I had KJN cut and drill my frame (With counterboring) which is a little cheaper than using the corners but also stronger. They will do it to your cad model, you could still use corners as well for extra strength.

Cost me £35 +vat for 18 holes with counterboring.

I already had the corners I did it for strength, I used m12 50mm A2 socket bolts.





A top tip if you do what I did make sure you get some corners then use them to get the extrusion straight before putting the bolt in when it's tight you can remove the corner and reuse.

Also 9045 extrusion takes M12!!!