Help on building an enclosure
Hello all. I am currently in the process of wiring up my electronics for my CNC router, but as money is tight, I don't really want to buy an enclosure. Is it easy enough to make one myself?
I have access to a water jet cutter at work so was thinking of just having it cut out of sheet metal ready to fold up like a cardboard box. However, as I am not very electronically minded I wanted to ask some basic (probably stupid) questions.
1. How big will my enclosure need to be? I am housing a standard off the shelf 48v PSU, along with the leadshine mx3660. How much free air space do I need to leave around them?
2. What material would be best? Ali or steel, or does it even matter? Can I paint it?
3. What other features should I incorporate? Such as a dedicated earth fixing point?
Thanks.
Re: Help on building an enclosure
Quote:
Originally Posted by
thomashomer1986
Hello all. I am currently in the process of wiring up my electronics for my CNC router, but as money is tight, I don't really want to buy an enclosure. Is it easy enough to make one myself?
I have access to a water jet cutter at work so was thinking of just having it cut out of sheet metal ready to fold up like a cardboard box. However, as I am not very electronically minded I wanted to ask some basic (probably stupid) questions.
1. How big will my enclosure need to be? I am housing a standard off the shelf 48v PSU, along with the leadshine mx3660. How much free air space do I need to leave around them?
2. What material would be best? Ali or steel, or does it even matter? Can I paint it?
3. What other features should I incorporate? Such as a dedicated earth fixing point?
Thanks.
Hi,
1. Why not layout all the bits you have and the work from there for an idea of size needed, you could also think about using some stand-off's (spacers) and make it multi leveled.
2. I dont think it would matter really, mine is a plastic type with a steel tray you screw in. I dont have the steel tray so plan to use some 5mm ali or somthing.
3. Do some reading up on the forums with regards to earthing, a single point, using star arrangement is the prefered method i believe, though you do need to pay more attention to the earthing, so best to have a read up as the answers are there.
.Me
Re: Help on building an enclosure
Quote:
Originally Posted by
thomashomer1986
1. How big will my enclosure need to be? I am housing a standard off the shelf 48v PSU, along with the leadshine mx3660. How much free air space do I need to leave around them?
2. What material would be best? Ali or steel, or does it even matter? Can I paint it?
3. What other features should I incorporate? Such as a dedicated earth fixing point?
1. I used Sketchup to draw my components in the form of boxes, save them as 'groups' that way you can rearrange them at will until you find the best layout. There's never much detail supplied about free air space other than with the VFD that likes about 75mm top and bottom.
2. Steel is the best, it's cheaper than aluminium, has better shielding properties than plastic, it's strong. Painting is the best idea, personally I like the grey that standard panels come in.
3. First thing is you want a removable back plate where all your components are mounted, steel is normal but aluminium would also be fine. The last thing you want is drilling holes in the panel itself to mount things.
It needs a hinged door because likely you will be mounting buttons etc. on it.
Normally they have a removable gland plate top and bottom where your cables pass through.
You might want to take into account cooling fans, these should be mounted to blow into the panel at the bottom drawing air through replaceable filters, this is keep air pressure inside the panel greater than that outside which keeps crap out, you will need an outlet at the top that does not let dust in by gravity.
You want an airtight gasket around the door when it's closed.
You might to fit a 'door interlocked isolator' for safety.
The panel itself, the back plate and the door should all be electrically connected to earth for safety, normally there is a stud spot welded to the inside of the door and one inside the panel, a short length of earth wire connects the two but still allows the door to open, the back plate is normally secured by four corner studs that raise it high enough above the back of the panel to clear nuts, etc. you used to mount components on the back plate with. The earth stud inside the panel can then become your 'star' earthing point.
You need a method of mounting the panel on a wall, this can be four holes in each corner of the back or a lug welded externally at each corner. Whichever way you choose you need to have access to these mounting points with all the guts installed in the panel.
Re: Help on building an enclosure
When building a Case from scratch it's always a good idea to build larger than needed to allow for expansion at a later date if required. The extra material cost is nothing but will be priceless when adding a new card or anything.
Steel is my prefered choice and Painting is ok but any Ground points will need cleaning back to metal. Regards Star grounding then you don't have to take all grounds back to the case. You can just use a Bus bar and run all to this point, then take Ground wire from this to Case.
Other things I would incorparate is a Fan to pull air out and filtered vent to let air be pulled thru. Two fans could be used but not required.
Re: Help on building an enclosure
Quote:
Originally Posted by
JAZZCNC
Painting is ok but any Ground points will need cleaning back to metal. Regards Star grounding then you don't have to take all grounds back to the case. You can just use a Bus bar and run all to this point, then take Ground wire from this to Case.
Yes I forgot to specifically mention that earth points must be free of paint, you need good contact to bare metal, star washers are a good idea as they bite into the metal.
Quote:
Originally Posted by
JAZZCNC
Other things I would incorparate is a Fan to pull air out and filtered vent to let air be pulled thru. Two fans could be used but not required.
I've found it's best to blow air in rather than suck it out. If you suck air out then crap can bypass the filter and find it's way in through gaps, holes, etc. because the air pressure inside the box is lower than outside.
We used to apply the same idea to complete electrical switch rooms.
Re: Help on building an enclosure
Quote:
Originally Posted by
EddyCurrent
I've found it's best to blow air in rather than suck it out. If you suck air out then crap can bypass the filter and find it's way in through gaps, holes, etc. because the air pressure inside the box is lower than outside.
We used to apply the same idea to complete electrical switch rooms.
Ermm I'm no expert on this so I'll bow to your greater experience Eddy but in a dusty enviroment directly sucking dusty air In will surely clog filters faster than pulling air out of a chamber.?
Re: Help on building an enclosure
Actually to create airflow (to the point of cooling) you need two intakes for every 1 exit. Providing filters are used on the intake dust shouldnt be a problem.
The idea is to, clean a filter, not an enclosure. Shop vac / filter should solve the dusty environment problem.
Re: Help on building an enclosure
Thank you everyone for your replies!
Right to start with then I am going to draw it out on inventor to get a better idea of the layout
Main points to consider then:
1. Steel or aluminium cover. (whatever my workplace has available)
2. Hinged lid, with an earth point to connect it to the main case
3. Raised steel platform for mounting the components onto. This is then earthed to casing.
4. Star grounded earth setup, maybe a bus bar to make earthing easier, which is then connecting to casing earth point
5. Additional space for upgrading.
6. Cooling fan and filter setup. 2 intakes/1 exit
7. Suitable mounting holes for attaching to wall etc.
Anything else?
One other question, I'm yet to get my WC spindle. Does VFD need to be mounted inside the enclosure as well then?
Re: Help on building an enclosure
Quote:
Originally Posted by
thomashomer1986
One other question, I'm yet to get my WC spindle. Does VFD need to be mounted inside the enclosure as well then?
Yes, read the manual regarding free space for cooling. For example mine needs no free space at the sides but needs 75mm clear top and bottom for cooling.
ABB model, top right
http://www.mycncuk.com/forums/gantry...html#post51392
Also at the bottom you can see the terminal rail, this doubles up as my earth bus bar because the earth terminals clamp onto the DIN rail which is earthed by the incoming supply cable.
Re: Help on building an enclosure
VFD Doesn't have to be inside the enclosure but like Eddy says it does need cooling space if you do.
To be honest I don't Like VFD inside same Enclosure because it introduces high potential for noise interference on other components.
Also I like to see the VFD display and have it Set to Amp's this way you can tell when cutter is getting worn has the Amp's rise has it wears.
Re: Help on building an enclosure
In the DIY context it sounds like personal preference dictates and other than the VFD cooling fan sucking in crap if it's not enclosed I don't suppose it matters, in an industrial setting it would always be inside the enclosure with suitable filtered vents for cooling. If the wiring and layout is done properly there should not be any problem with interference.
I don't know about the Chinese VFD's but I'm used to using those with a control panel that can be mounted on the front of the enclosure set to view whichever parameters you want.
I'll give an example about the cooling fan.
At one place I worked the environment was quite dusty but not that you could see it floating about in the air. Some inverters were installed in 2m tall cabinets with vents for air intake, the vents were not filtered because the air did not seem that bad. After a month or two one of the drives failed, eventually it had to be sent back to the manufacturers for examination. It was found that the two internal cooling fans blast air over the control boards than onto the power devices, this is how it should be, but where the boards had double sided track, the connecting ferrules had been 'sand blasted' away by the dusty air being blow over them. The answer was to fit replaceable filters to the cabinets and spray a better conformal coating (they called it tropicalising, just lacquer at the end of the day) over the boards.
Re: Help on building an enclosure
Quote:
Originally Posted by
EddyCurrent
In the DIY context it sounds like personal preference dictates and other than the VFD cooling fan sucking in crap if it's not enclosed I don't suppose it matters, in an industrial setting it would always be inside the enclosure with suitable filtered vents for cooling. If the wiring and layout is done properly there should not be any problem with interference.
Fully understand what you mean Eddy but end of the day we are in a DIY setting and building to industrial level is prohibitly expensive to do correctly and often massive overkill in a DIY enviroment. The problem I've found with interference comes not so much from Incorrectly wired or layout but more from crappy sensitive electronics like Chepa Bob's etc which you often find in DIY enviroments. This is why I won't use Cheap Bob's Drives etc anymore they are just a Pain in the arse.!!
Regards the out of cabinet VFD and Front panel then Yes with Chinese VFD's you can wire the front Panel and fit to front of enclosure but that then means having Enclosure located where it can be seen and often you'll want that out the way under machine or some other inconvenient location.
Where has placing VFD close by the machine is relatively easy and doesn't require messing around with extending wires or buying expensive Add-on cards Etc.
Really like you say it's down to individual preferance at this level. End of the Day we just need to be safe and not worrying about making some HSE boff happy and limiting the potential for Baldness inducing problems.:ambivalence:
Re: Help on building an enclosure
Quote:
Originally Posted by
JAZZCNC
Really like you say it's down to individual preferance at this level.
But don't be thinking I'm going soft ! :hysterical:
