Little Brute

[FandZ]

This is my first build. It’s in the works as you can tell. It’s a desk top wide router gantry style. The materials used are all hardware store bought. It is mostly comprised of steel squares and aluminum. So for I have the table and X axis rollers done.

I don’t think it’ll win any beauty contests and certainly isn’t as suave as a lot of the builds going on, but what it lacks in style, it makes up in rigidity and strength( I hope at least lol). It can handle me standing on it with no real noticeable deflection 

The goal for this machine is to work aluminum and copper as well as odd wood jobs.

As you can see, right now I have the rollers on an aluminum square. Deflection isn’t a problem but I can tell wear may be in the long run. I’ll be using steel squares as the final rails. I’ve already tried the roller assembly on steel and I was quite satisfied with the results.

On the roller assembly, I’ve tried various configurations from bearings in the middle, to one at each corner. I’ve even tried 8 bearings and 16 bearing configurations. This 8-bearing catty corner setup felt just as strong as the 16 bearing all square setup.

As you can see, the roller assembly is easily adjustable, the side bolts bring the upper bearings closer and visa versa. The first set I made I didn’t go for any sort of accuracy with the holes I drilled. But still it rolled very smoothly and tightly. On the second set, I used my caliper to scribe cross lines and a punch to mark my spot to drill. Then I drill a small pilot hole and finished up with a 5/16. To my satisfaction, once I assembled it and adjusted it, the wear on the bearings was dead center, showing it was square to the rail. Hopefully over the upcoming weekend I’ll take some wear picture of the more accurate roller assembly. The ones below are of the first set.
As you can see the rails go further out in the back. The reason is to give the router as much cutting access to the table as possible. Also, you’ll notice the rails are under and slightly towards the center. The reason for this is to protect the bearings from debris and to help center the gravity because it is a wide table. I’d hate for it to start dancing a jig on desktop..lol

I plan on using an acme screw in the center and am thinking about belt driving it from a stepper motor. I’m looking to get some great resolution and torque out of it. I hope someone can advise me on this and really point me in the right direction once the time comes. I hope to start buying my electronics around the end of the month.

I’m going to take this weekend off of building and focus on tidying up the machine. There are a lot of jagged edges that need a good filing. Also I have a hodge podge of bolts and washers. I hope to get all that uniform and maybe do a little sanding here and there to give it a cleaner appearance.

If you have any suggestion please let me know. A lot of this is new to me, including drilling and working with metal. I think I’m on the right track but it is always good to hear from you seasoned pros and you newbies like me.

[FandZ]

And two more pictures. For some reason my camera makes it look like the top is curved but it is flat.

[FandZ]

Hi all, below is a picture of the gantry design I'm contemplating making. I'm also attaching a sketch up file incase anyone wants to review it. I'm thinking about making this out of half aluminum and steel. I'll probably just do it all out of steel but I'm thinking if the gantry rails are steel the supports and side beams can be aluminum. Choices choices.

[FandZ]

Decided to do a little youtube video of how smooth and sturdy the roller assembly is.

[wadoman]

Wow you are a true DIYer! That roller assembly looks smoother than my V-wheel setup! They look like they can be adjusted very easily to get zero play.
I think the name brute works. nice work

[FandZ]

Wow you are a true DIYer! That roller assembly looks smoother than my V-wheel setup! They look like they can be adjusted very easily to get zero play.
I think the name brute works. nice work

Thanks for the compliment. Play in the roller assembly is no issue. You just adjust until you hit that sweet spot. Hopefully, next week I'll see how it is with the gantry on. If I notice any racking I'll just tighten it till it's gone.

[FandZ]

Hey guys. Looks like I'll be ordering a G540 this upcoming weekend. I really need some advice on a power supply, stepper motor, and whatever odds and ends I'll need to get it rolling. I'd like to order it all this weekend.

I'm not good at soldering. So I'm looking for as close to a plug and play solution I can get but I don't want to sacrifice quality to save me from a few wires.



I'd really like to get three Keling KL23H2100-30-4BM (1/4” Dual shaft with a flat) 495 oz-in. I think it is overkill for my needs but I do know I'll be building a bigger unit down the road. One thing that concerns me is only one stepper on that page says it can be used with a g540.

I'd like to spend around 700.00 or less. But I can go a little higher if it is justifiable.

[Crevice Reamer]

Hi FandZ. Marvelous design! Those look to be some really great kids you have there.

Let's talk about that wide gantry. Are you SURE that you can drive it reliably with a screw in the center? It wouldn't take very much misalignment to cause binding. Most gantries that wide use a slaved stepper on each side to get good performance. This requires two drivers, but Mach3 sees both as one axis. Two slaved motors could be much smaller, faster, and more likely be in the G540 range.

Let's talk stepper motors. The Torque rating is what you get with the motor at rest. Torque falls off with increase in RPMs. To do any WORK with it, you need to carry much of that torque up to higher RPMs.

It is important to match the motor to the load. You can't just assume that bigger is better. Bigger motors run somewhat slower than smaller motors. A router, more so than a mill, needs high rapid speeds. You will get best performance by wiring the motors in Bipolar Parallel.

The way to get best rapid speeds is to be able to get torque at high RPMs. This is accomplished by matching the motor's best voltage to the power supply voltage. Higher voltage pulses charge the coils more quickly and maintain torque to faster speeds.

Using the G540 as the controller, (and you should, it's the most bang for the buck) You can operate with a max voltage of 50V. Formula for best voltage of a stepper motor is 32 times the square root of the inductance. With the G540, you will want motors with best Voltage between 50 and 65V.

Let's look at that 495 Oz motor. It has an inductance of 7 mH. Using the formula, it has a best Voltage of 85V. Fifty Volts will seriously under-power it, resulting in slower rapids. A $180 72V PSU would run it faster, but then you would need to go with G203Vs to get the same features available in the G540 and that would be way more expensive. ($560 just for them)

I would recommend the $39 60V Keling 270 OZ KL23H276-28-4B. It's already wired Bipolar Parallel internally, so only 4 wires to connect.

http://kelinginc.net/KL23H276-28-4B.pdf

Three of these would be very efficient for X and Y, and, depending on weight of your router head, might also be OK for the Z axis. If not, then the currently out-of-stock $49 65V Keling 387 ouncer would be your best bet.

The $60 Keling 48V 7.3A PSU would power these very nicely.

CR.

[FandZ]

Thanks for the complements on the kids and design. I can only take credit for one of those, my wife had something to do with the other.

I really do think I won't have a problem driving it straight from the middle. I've connected a square tube across the top of the rollers and tried to get it to slack up. Let's just say, I ended up with bruised shins and tail bone and the Y axis won. When I get my gantry on I'm going to hang one of those 50lbs weights with wire on one side ( with children out the room) and let it rock to see if anything racks while I run it through its motion. Fingers crossed

Thank you so much for your advise. It all made great sense and I'm going to follow it to the T.

I'm researching if I should drive it directly or use a belt and gear system to drive the lead screw. With the belt it will probably make my rapids even faster It still all is a little murky. I'll probably do direct drive to make it easier on me at first though.

If you could, I have just a few more questions.

with the g540, do you have any recommendations for a mountable quick stop?

Also what gauge wire would you recommend I use between the stepper/drivers/ and power supply?

And final Q, besides a fan cooled case to house everything and a printer cable, are there any other odds and ends I should get? It's horrible when you have everything you need but one little screw or bolt lol.

Thanks so much for you help and advice.

Chris

Hi FandZ. Marvelous design! Those look to be some really great kids you have there.

Let's talk about that wide gantry. Are you SURE that you can drive it reliably with a screw in the center? It wouldn't take very much misalignment to cause binding. Most gantries that wide use a slaved stepper on each side to get good performance. This requires two drivers, but Mach3 sees both as one axis. Two slaved motors could be much smaller, faster, and more likely be in the G540 range.

Let's talk stepper motors. The Torque rating is what you get with the motor at rest. Torque falls off with increase in RPMs. To do any WORK with it, you need to carry much of that torque up to higher RPMs.

It is important to match the motor to the load. You can't just assume that bigger is better. Bigger motors run somewhat slower than smaller motors. A router, more so than a mill, needs high rapid speeds. You will get best performance by wiring the motors in Bipolar Parallel.

The way to get best rapid speeds is to be able to get torque at high RPMs. This is accomplished by matching the motor's best voltage to the power supply voltage. Higher voltage pulses charge the coils more quickly and maintain torque to faster speeds.

Using the G540 as the controller, (and you should, it's the most bang for the buck) You can operate with a max voltage of 50V. Formula for best voltage of a stepper motor is 32 times the square root of the inductance. With the G540, you will want motors with best Voltage between 50 and 65V.

Let's look at that 495 Oz motor. It has an inductance of 7 mH. Using the formula, it has a best Voltage of 85V. Fifty Volts will seriously under-power it, resulting in slower rapids. A $180 72V PSU would run it faster, but then you would need to go with G203Vs to get the same features available in the G540 and that would be way more expensive. ($560 just for them)

I would recommend the $39 60V Keling 270 OZ KL23H276-28-4B. It's already wired Bipolar Parallel internally, so only 4 wires to connect.

http://kelinginc.net/KL23H276-28-4B.pdf

Three of these would be very efficient for X and Y, and, depending on weight of your router head, might also be OK for the Z axis. If not, then the currently out-of-stock $49 65V Keling 387 ouncer would be your best bet.

The $60 Keling 48V 7.3A PSU would power these very nicely.

CR.

[Crevice Reamer]

.....with the g540, do you have any recommendations for a mountable quick stop?

Yep, $10:

http://kelinginc.net/CNCPackage.html

Also what gauge wire would you recommend I use between the stepper/drivers/ and power supply?

Use stranded wire of as large as will fit into the terminals and no more than 18 inches long. 18 gauge should be fine.

And final Q, besides a fan cooled case to house everything and a printer cable, are there any other odds and ends I should get? It's horrible when you have everything you need but one little screw or bolt lol.

Thanks so much for you help and advice.

Chris

Mach3 $175--Less if you buy it from Keling with motors.

Easy cam program integrates with Mach 3 and allows part design and gcode generation for $69:

http://www.d2nc.com/

You will also need some other stuff:

A straight through male to male DB25 parallel cable:

http://www.cnc4pc.com/Store/osc/prod...products_id=76

You can use THIS wire for motor cables and home/limit switches. Ground the drain wire ONLY at the driver end.

http://cgi.ebay.com/Servo-Motor-Wire...3286.m20.l1116

You won't need any db9 motor connectors with the G540, as they come WITH it. You WILL need 1/4 watt current limiting resistors, 1K ohm for each motor amp. (IE: 2.8A motor = 2.8K Ohm resistor) one for each motor. You can get them here:

http://www.digikey.com/

If you don't already HAVE them, these are excellent home switches:

http://cgi.ebay.com/ws/eBayISAPI.dll...%3D4%26ps%3D42

They are NO, so only for home switches. Limit switches need to be NC. the whole set of 6 switches costs less than ONE switch would cost at Radio Shack.

These limit switches cost $2.99 EACH:

http://www.use-enco.com/CGI/INLMKD?S...01=1&SICOUNT=1

You can buy a custom G540 case here:

http://www.seanet.com/~dmauch/

You may also want some of this energy chain:

http://www.aboveboardelectronics.com...ain/index.html

CR.

[FandZ]

Thanks so much for all the links and information. Time to bust out the plastic fantastic.

Originally, My goal was to have it up and running by mid march but Now I'm thinking I should have it done by mid February, just working a few hours on the weekends.

I watched some video's on d2nc. Man I'm pumped. I'm going to try my hardest to get the gantry and z axis done this weekend.

Yep, $10:

http://kelinginc.net/CNCPackage.html



Use stranded wire of as large as will fit into the terminals and no more than 18 inches long. 18 gauge should be fine.



Mach3 $175--Less if you buy it from Keling with motors.

Easy cam program integrates with Mach 3 and allows part design and gcode generation for $69:

http://www.d2nc.com/

You will also need some other stuff:

A straight through male to male DB25 parallel cable:

http://www.cnc4pc.com/Store/osc/prod...products_id=76

You can use THIS wire for motor cables and home/limit switches. Ground the drain wire ONLY at the driver end.

http://cgi.ebay.com/Servo-Motor-Wire...3286.m20.l1116

You won't need any db9 motor connectors with the G540, as they come WITH it. You WILL need 1/4 watt current limiting resistors, 1K ohm for each motor amp. (IE: 2.8A motor = 2.8K Ohm resistor) one for each motor. You can get them here:

http://www.digikey.com/

If you don't already HAVE them, these are excellent home switches:

http://cgi.ebay.com/ws/eBayISAPI.dll...%3D4%26ps%3D42

They are NO, so only for home switches. Limit switches need to be NC. the whole set of 6 switches costs less than ONE switch would cost at Radio Shack.

These limit switches cost $2.99 EACH:

http://www.use-enco.com/CGI/INLMKD?S...01=1&SICOUNT=1

You can buy a custom G540 case here:

http://www.seanet.com/~dmauch/

You may also want some of this energy chain:

http://www.aboveboardelectronics.com...ain/index.html

CR.

[Crevice Reamer]

Use red and black (Or two different colors like black and white) wire for power connections to G540. Make sure you connect plus to plus and negative to negative. Do NOT let any stray strands bridge between the terminals. Wiring this backwards or shorting across, can kill this unkillable drive.

Bon Voyage!

CR.