[Phife]

Hey everyone,

Ive been wanting a smaller, stronger machine for some time. My last machine suffered from unsupported rails and flexed a lot. It worked well but caused some issues. Recently ive been doing a lot of Stainless Steel engraving with it and while it works well for that (deepest cut is 0.003) It wasnt ideal and very hard to maintain a flat surface to engrave on as it was large and moved a lot with temperature and time.

This newest machine that I have been designing in Sketchup will have a working area of around 32"x21"x12". It will have a swappable tool holder that will hold either , a 60'000rpm spindle from Keling, a 3D Extruder from the Makerbots or a standard 2.2kw Spindle.

I designed the Z axis to be as rigid as possible, I feel this design should accomplish this as the entire Y gantry will raise and lower making it pretty much just as rigid at the top of the Z as it is at the bottom.

Im using the following parts:

-Gecko G540, w/ the Gecko Nema23 Steppers (4 Steppers)
-Keling 300W 60000rpm spindle with VFD.
-Misumi 6 series extrusion and brackets, 120x60 for the gantry and 60x60 for most everything else.
-Glacern SBR20 Rails (2 sets of 960mm and 2 set of 480mm)
-Linearmotionbearnings 1610 Ballscrews.

I am using many parts from Misumi, its a great site with lots of information and even downloadable 3d drawings of most of their parts, I used them in this model.

I am even using a Rotating Ball Nut design on my long gantry axis, I choose a double row AC mounted bearing, added a sleeve that I will have to get made and a Timing pulley, all from Misumi. I expect it to work fairly well, and Its mostly an experiment. All other traditional designs for the ballscrew were going to take up too much room, the Rotating nut is very compact and the stepper and all the rotating nut parts fit inside the Gantry Carriage.

I am looking for some feed back on the design, especially the UN-conventional Dual Z axis.

I have yet to purchase the parts from Misumi until I have a finished design. I already have most of the other parts. I expect to have this done in about a month.

I will use it for engraving at first and then add the 3D print head on afterwards. The long Z travel is mostly for 3d Printing. I am still working on the placing the brackets for the two Z motors that will go on the top of the gantry uprights and the table motor which will hang under the table.

[louieatienza]

Hey everyone,

Ive been wanting a smaller, stronger machine for some time. My last machine suffered from unsupported rails and flexed a lot. It worked well but caused some issues. Recently ive been doing a lot of Stainless Steel engraving with it and while it works well for that (deepest cut is 0.003) It wasnt ideal and very hard to maintain a flat surface to engrave on as it was large and moved a lot with temperature and time.

This newest machine that I have been designing in Sketchup will have a working area of around 32"x21"x12". It will have a swappable tool holder that will hold either , a 60'000rpm spindle from Keling, a 3D Extruder from the Makerbots or a standard 2.2kw Spindle.

I designed the Z axis to be as rigid as possible, I feel this design should accomplish this as the entire Y gantry will raise and lower making it pretty much just as rigid at the top of the Z as it is at the bottom.

Im using the following parts:

-Gecko G540, w/ the Gecko Nema23 Steppers (4 Steppers)
-Keling 300W 60000rpm spindle with VFD.
-Misumi 6 series extrusion and brackets, 120x60 for the gantry and 60x60 for most everything else.
-Glacern SBR20 Rails (2 sets of 960mm and 2 set of 480mm)
-Linearmotionbearnings 1610 Ballscrews.

I am using many parts from Misumi, its a great site with lots of information and even downloadable 3d drawings of most of their parts, I used them in this model.

I am even using a Rotating Ball Nut design on my long gantry axis, I choose a double row AC mounted bearing, added a sleeve that I will have to get made and a Timing pulley, all from Misumi. I expect it to work fairly well, and Its mostly an experiment. All other traditional designs for the ballscrew were going to take up too much room, the Rotating nut is very compact and the stepper and all the rotating nut parts fit inside the Gantry Carriage.

I am looking for some feed back on the design, especially the UN-conventional Dual Z axis.

I have yet to purchase the parts from Misumi until I have a finished design. I already have most of the other parts. I expect to have this done in about a month.

I will use it for engraving at first and then add the 3D print head on afterwards. The long Z travel is mostly for 3d Printing. I am still working on the placing the brackets for the two Z motors that will go on the top of the gantry uprights and the table motor which will hang under the table.

Pretty cool... There is a guy I believe in Germany that built a moving gantry design, with a gantry that raises and lowers for the z. I saw the video on YouTube a couple years ago, but don't have the link. I can't remember if the bridge moved independently of the spindle...

Really impressed with Misumi's site as well. Just bought wxtrusions this time, but will look into their mechanical components in the future...

[Phife]

Misumi website is great, I hope their service and parts are just as good.

Some more details,

I choose the 6 Series extrusion because it has a 30mm slot spacing, which lines up with the hole spacing on the SBR20 series Supported rails from Glacern and from Linearmotionbearings on ebay. This should make the entire machine easier to build.

I will most likely be using 1/2" Aluminum for all the various plates, although I am considering 3/4", Im not sure if the 1/2" will be strong enough.

I will use a 1/2" aluminum plate for the table and I will bolt on some aluminum extrusion for the table.

I plan to use vacuum fixtures made from aluminum plate to hold the various metal parts I engrave, the table will have flood coolant so it will be liquid friendly, I plan on making some covers for the exposed rails/screw and make it so it channels the coolant into a bucket under the table to allow the chips to settle out and be filtered then the coolant can recirculate.

I hope to keep this under $6000 total.

I will use mach 3.


I have some concern as to the speed of the steppers, Im not really familiar with Steppers and how they work as my last machine used servos. I will be using a timing belt and pulleys to drive my rotating nut, The only combination of pulleys I could find that would work with my ball nuts and steppers are a 2:1 ratio, I know I will get more torque this way but Im losing speed, and with my 10mm lead ball screws Im worried It will be a bit slow.

Does 750RPM for the Gecko Nema23 steppers sound like a resonable speed? does anyone know if there is a torque curve for the Gecko Nema23 steppers?

[louieatienza]

Misumi website is great, I hope their service and parts are just as good.

Some more details,

I choose the 6 Series extrusion because it has a 30mm slot spacing, which lines up with the hole spacing on the SBR20 series Supported rails from Glacern and from Linearmotionbearings on ebay. This should make the entire machine easier to build.

I will most likely be using 1/2" Aluminum for all the various plates, although I am considering 3/4", Im not sure if the 1/2" will be strong enough.

I will use a 1/2" aluminum plate for the table and I will bolt on some aluminum extrusion for the table.

I plan to use vacuum fixtures made from aluminum plate to hold the various metal parts I engrave, the table will have flood coolant so it will be liquid friendly, I plan on making some covers for the exposed rails/screw and make it so it channels the coolant into a bucket under the table to allow the chips to settle out and be filtered then the coolant can recirculate.

I hope to keep this under $6000 total.

I will use mach 3.


I have some concern as to the speed of the steppers, Im not really familiar with Steppers and how they work as my last machine used servos. I will be using a timing belt and pulleys to drive my rotating nut, The only combination of pulleys I could find that would work with my ball nuts and steppers are a 2:1 ratio, I know I will get more torque this way but Im losing speed, and with my 10mm lead ball screws Im worried It will be a bit slow.

Does 750RPM for the Gecko Nema23 steppers sound like a resonable speed? does anyone know if there is a torque curve for the Gecko Nema23 steppers?

I'm extremely pleased with the parts I got from Misumi. The cuts were all accurate and burr-free on the extrusions. The gussets were qually well-made. These GFS extrusions have some serious heft to them. The nuts and screws were also well packaged and of high quality.

I actually went down from 1" aluminum plate to 3/4" on my current build for the table surface, to make it viable to ship UPS, otherwise I'd have to pay freight. For the other plates, I plan to use a mix of 1/2", 3/4", and 1" where I feel it would be appropriate.

CarveOne says he's getting arough 700ipm with his Gecko540 and steppers, on his smaller router. The spinning nut design should at least equal that...

A note about Misumi... if it's your first order, you get a 30% credit toward your second order, up to $150, so you might want to plan your order accordingly.

[CarveOne]

(snip)

CarveOne says he's getting arough 700ipm with his Gecko540 and steppers, on his smaller router. The spinning nut design should at least equal that...

(snip)

That's with 75khz pulse rate, 5 start (very straight) lead screws and near perfect alignments. It's down to around 550 ipm at 45khz and/or any drag at all in the carriages. 700 is very "iffy", but it's good brag factor. I wouldn't count on it for cutting anything. After my latest gantry upgrade I'm having trouble getting a reliable 600 ipm. There may be an alignment issue after removing the lead screws for that rework.

The rotating nut will certainly help. With 8 start lead screws there will be more speed, and a little less accuracy.

CarveOne

[Phife]

My plan for the rotating nut is to use the RM1610 Ballscrew and Nut from LMB2008 on ebay and have the screw securely fixed on either end to the gantry side plates with a lock nut.

So no leadscrew, I dont know how the 10mm lead ballscrew compares to the 5 start or 8 start leadscrew.

Can you give me an idea of what sort of range of RPMs you can achieve? Max RPM? Peak power RPM?

Im worried that 10mm lead is not enough, but I dont know how fast a stepper can really turn. Say I get 500RPM from the stepper, after the reduction its only 250RPM and at a 10mm lead I get 2500mm/m which is only about 100IPM. I dont need to go super fast as its a small machine, but I would like to at least get 200IPM which would require the stepper to turn at 1000RPM. Maybe I should switch over to servos? or will the stepper be able to turn that fast?

Im using a 48v 12A PS.

[ger21]

You should be able to get around 1000rpm.
I can get 800rpm with a Xylotex and 24V.

Carveone's 700ipm = 1400rpm. The ballscrew is about 20% more efficient than the acme, too.

Since you are using a 2:1 reduction, you might want to see if you can get a 1620 screw.

[louieatienza]

You should be able to get around 1000rpm.
I can get 800rpm with a Xylotex and 24V.

Carveone's 700ipm = 1400rpm. The ballscrew is about 20% more efficient than the acme, too.

Since you are using a 2:1 reduction, you might want to see if you can get a 1620 screw.

Not sure how good the positional error is on high lead (lead => screw diameter) rolled ballscrews. Maybe it would be better to use the 10mm lead ballscrew and a 1:1 gear ratio?

[cyclestart]

SDPI lists 1/4" bore XL pulleys up to 30 teeth. Whether it's wise to use a steel pulley that large on a stepper I couldn't say but I bought one for my own spinning nut (work in progress).

The sleeve will be threaded on the OD to hold the works together?

[Phife]

I am using AT5 aluminum pulleys from misumi.. I the largest pulley they have in that type with a 6.35mm bore is a 20Tooth, the Pulley on the ballscrew is a 40Tooth. Its the smallest size pulley that will still allow the 38mm bolt hole pattern that matches the ballnuts hole pattern.

I am going to thread the OD of the sleeve near the back to lock everything together and the sleeve will also have threaded holes at its flange to sandwich the nut between the pulley and sleeve.

The only other option I have to get more RPM would be to go to a 3/8" shaft stepper, use a servo, or a higher lead screw.

Ive been looking and chai does not sell 20mm lead ballscrew, the ones they sell everywhere else are a lot more expensive. Im only paying $65 for the long axis screw and nut. Everywhere else is over $200.

So I think I will just see how well this setup works and if its too slow for my liking I will find a 3/8" shaft stepper and get a larger drive pulley to reduce my ratio.

[cyclestart]

That style of belt claims some advantages over XL belts including eliminating backlash. Oh well, too late for me now.

Any feedback on what misumi is like for a Canadian hobbyist will be appreciated. Customer service at SDPI was friendly enough but a box weighing a pound or so cost $68 for delivery including all the usual UPS annoyances.

EDIT/ the $68 included 12% taxes on the ~$70 dollar value. Can't blame UPS for collecting that

[Phife]

Some of my parts arrived, Glacern SBR20 Rails, Spindle and VFD (this thing is tiny!) and the beginnings of the control box.

Rails look smaller than I expected, im sure they will work but I had imagined them to be bigger, same with the 300W 60,000rpm spindle, its very small only 2" diameter and 5" long, ER8 collet which should be fine for the engraving as I only use 1/8" tooling.

I priced out most of the rest of the Misumi components, im surprised, it seems like I may come out under budget!

In case anyone is wondering what parts I used for the rotating nut, heres a quick breakdown.

Rotating Nut: ~$340 + Collar Machining (Drilling Flange and Threading the end for the locknut) ($100est)

TTPA40-AT5100-A-H17-KFC38-K6 Timing Pulley (40Tooth) - $31.60
BRN35 Locknut - $7.67
BGHWB6007ZZ-50-50 T-Housing Double Row Bearings - $172.23
U-FTCLC-V1.110-D1.38-H1.90-T0.312-L3 - Flanged Collar - $58.19

Ballscrew and Nut from Chai - $70 (such a good deal! even includes end machining for the ridgid end mounting)


So for around $450 I get a rotating ballnut in a nice compact system, I'll let you guys know how it works when I build it.

Heres some pics of the parts.

[Phife]

Heres the latest drawings for the Rotating Nut using the parts I listed.

[harryn]

Rotating Nut: ~$340 + Collar Machining (Drilling Flange and Threading the end for the locknut) ($100est)

TTPA40-AT5100-A-H17-KFC38-K6 Timing Pulley (40Tooth) - $31.60
BRN35 Locknut - $7.67
BGHWB6007ZZ-50-50 T-Housing Double Row Bearings - $172.23
U-FTCLC-V1.110-D1.38-H1.90-T0.312-L3 - Flanged Collar - $58.19

So for around $450 I get a rotating ballnut in a nice compact system, I'll let you guys know how it works when I build it.

Heres some pics of the parts.

Thanks for posting this info, it is really useful. I like rotating nut designs, but those dang bearings are so expensive. For just one axis it is ok, but put in 5 of these and it adds up.

[Phife]

Ya I agree, those bearing blocks are fairly pricey but after holding them in my hand I can see why, they are really nice, large and solid looking pieces. I dont think you would need 5 of them for any machine, Maybe a couple for a long axis or if you are doing a design like mine you only need one for the long axis.

Also, it reduces the cost of the ballscrews as you do not need the Fixed and Floating ends anymore, this should save anywhere from 60-120$ almost making up the cost of the mounted bearing.

Also you can reduce the diameter of the ballscrew since you dont need the thickness to reduce whipping, I could have probably gone with a 12mm ballscrew but I felt the 16mm was a good compromise.

[Phife]

I got the frame assembled and most of the parts here, I will post some pictures of where im at later today or this weekend.

[Phife]

Well its been a while since my last update, Its taken me longer than expected to get this thing put together. I hope to have it all done by the end of May. Heres some pictures of my progress so far.

Theres a picture of my spindle and VFD, this thing is tiny, but can engrave at 50000rpm.

Also some pics of the machine frame.

[Phife]

Heres some pictures of my rotating nut, and a close up of the frame.

[Phife]

Some pictures of my Ethernet Smoothstepper which I will use to control the machines 4 Stepper motors and also control the Stepper to drive the Extruder for the 3D printer.

Next to the smoothstepper is my Gnexlabs Controller Card which has the ability to control 2 Extruder hot ends and the heated bed, it has a small LCD which allows you to set the temps and various other settings for the 2 Thermistor inputs and the 1 Thermocouple input.

Im using Geckos Nema23 Steppers for my machines axis and I'll use a Nema17 to drive the extruder.

And a picture of the entire machine after I installed the 60lb bridge, I am concerned a bit that my dual Nema23 motors wont be able to move the bridge gantry when its fully completed, I expect it to weight around 75lbs once everything is mounted. If they have trouble I will add either a counter balance or a gas shock to help with the load.

[harryn]

Nice job on those rotating nut setups. I think with the mechanical advantages designed in, it will move just fine.