Looking to build in Chicago

[CNC On The Brain]

Hi All,

I wanted to start out by saying Thank you to everyone (I mean everyone as I have read so much) who contrbutes on this forum, as you all have provided a level of insight and knowledge that is not normally found and that i personally find encouraging. Second it is great to know that there are others like myself who are (as my wife says) strange and willing to spend a bunch of time researching an item just to gather the information and "do it". I also would like to say a "Special" thank you to Mike (Metalhead) and Gerald for providing and maintaining the forum for the use of all.

Now to the potential build (once i get approval from the boss) and one of the resaons I am writing now. I am looking to build a 5' x 10' or 12' table to machine normally flat materials into a variety of items. I have purchased the plans and have read them until I feel I have an understanding of all of the build features (Gerald thank you for the fantastic layout of the plans I know some architects who could take a lesson from you). I have a bevy of tools but have little metalworking ability (i have never had the opportunity) but look forward to learning. Its kind of funny I am a materials inspector by trade and an AWS Certified Weld Inspector but have never laid a bead. I think I am stuck on the same point that others have and looking for some advice on Motor selection. i am looking to keep the price as reasonable as possible (i think i can use my work connections to get the steel very reasonably) and the Motors/Driver portion seems costly. I have seen that the best results come from Geckos and O/M motors but i have found these
http://www.ebay.com/itm/4Axis-Nema-3...item3f06d69e1c
from Longs and was wondering if they would work?? I have noticed that they have a very high phase inductance (15) but i am thinking that would only effect the power supply and potential heat. They are very reasonably priced and I was wondering if they would work or if there would be potential downsides that I am missing. Also would there be the ability to upgrade to geckos/PMDX board in the future or would the motors not allow that?

Thanks in advance for any responses.

[bradm]

Stepper motor designs tend to come in three different lengths for any given standard size. The standards set the size of the mounting plate, which constrains the height and width of the motor body. The three lengths correspond to a "single stack", "double stack", or "triple stack" motor - essentially how many sets of windings are placed next to each other along the shaft.

Triple stack motors give you more torque, at the expense of more inertia and indent torque to overcome, and thus can have lower real world top speeds than a single stack motor when driven with similar drivers.

Gecko's designs generally work well with NEMA34 single stack, NEMA23 triple stack, and smaller motors.

Most of the experience on this forum is related to single-stack NEMA34 motors, either geared or belt drive reduced.

The motors you are looking at appear to be double stack NEMA34s at a glance, which means they will most likely never be a good match for gecko drivers. They can surely drive the MM; the areas to watch out for would be lowered resolution due to inconsistent microstepping, and lower top speed. Chances are they will be good enough, but we can't tell for you - you'll have to tell us after the experiment.

Also, you could watch http://www.mechmate.com/forums/showthread.php?p=56507 which appears to have the same, or a similar set of motors.

[danilom]

15mH inductance, watch for that. Ebay is flooded with these motors.

[Kobus_Joubert]

Have a look at LONGS motors website. They have motors with the same spec. as the MotionKing 34HS9801 , but at a cheaper price. I have used them lately and they work for me.

[CNC On The Brain]

Thank you all for the response...it helps. I need to keep the price reasonable to build or regretfully the "boss" will have none of it. I keep telling her it could eventually lead to me being home more and I think i may have scared her a bit.

Bradm that actually makes sense and helps immensely and i have been watching exploro's build which is what caused me to look at Longs in depth. But ended up scratching my head at a 1600 oz/in motor that he was intending to use.

Danilo you are absolutely right all of the motors available on ebay seem to have a phase inductance of 15 or 22.

Kobus i will take a deeper look and are you using Geckos or a Longs Driver?

Again thank you for the help.

[domino11]

Glen,
Have a look here for large motors Why a stepper motor should not be too big . . . .
Kobus is still using these drivers as far as I know UIROBOT Stepper Drives

[CNC On The Brain]

Heath,

Thanks for the reminder about Gerald's motor size post....i find that i have read many of the posts but as my understanding of the mechanics grows so does my understanding of what I read. Hence i need to keep reading or is that re-reading!!!

I have read Kobus' build thread along with many, many, many others and looked again and you were right he has UIRobot drivers but they dont seem to be much if any cost savings. I think I could utilize a G540 and still be able to upgrade in the future (I think it may be my direction). But still pondering....Oh and reading.

[Kobus_Joubert]

Hi Glen, I use UIROBOT drivers on my MotionKing and Longs Motors without any problem so far. I find the UIRobot very cheap....As I am the agent for them in South Africa I get them a bit cheaper I suppose.

[CNC On The Brain]

I have been away abit with work and have had to put the project on hold but i am hoping to start moving forward again. I have gotten quotes for various items and am looking to put together a budget prior to starting so I can keep it reasonably priced. I am still looking at a cutting area of 5 x 10.

I think i have decided on a motor/driver configuation. My concern is with the Power Supply and wanted to get some confirmation of my numbers.

The motors and drivers will both come from Deitech. I have gottena price from them and it is pretty reasonable even with shipping. Also looking at some of the builds the selected motor/driver seem to function well. The quote is below for those of you that are interested. Claudia responded quickly and has replied to my questions. Dont pay any attention to the pulley sizes listed they were just tossed in to get an idea of costs.

86HS9801 stepper motor: USD48.00/pc x 4 pcs = USD192.00
DM856 stepper driver: USD65.00/pc x 4 pcs = USD260.00
Timing pulley 15XL: USD6.00/pc x 4 pcs = USD24.00
Timing pulley 72XL: USD25.00/pc x 4 pcs = USD100.00
Timing belt 300-XL-10: USD3.00/pc x 4 pcs = USD12.00
HF spindle DTS-23: USD238.00/pc x 1 pc = USD238.00
ER20 collect chuck: USD6.00/pc x 3 pcs = USD18.00
To ship above goods to 60401 Illinois U.S.A by FedEx, the shipping cost is USD122.00, so totally it's USD966.00 for you to get them in door.
Yes, we have the matched VFD for spindle DTS-23, the price is USD218.00, and we have 68V/5A switching power supply for the above motor and driver, the price is USD55.00.

The stats of the motor are Current of 4amps and inductance of 4.1 model 86HS9801. The drivers are Leadshine DM856 listed as input voltage of 20-80 and output iof 5.6 max.

I have calculated a required voltage of 64.8 at 695VA. I would like to get an Antek power supply and it puts me with the model number PS6n63 series as the closest match. Am i in the range of where i need to be? Or am i completely off-base.

Also the prices from Rick at Superior bearing are below:
GW3 = $15.95ea @ 14pcs = $223.30
B3X = $3.81ea @ 6pcs = $22.86
Total Parts = $246.16
Still very reasonable.

Also Tim at Standard Steel on Part Number 200011 (73") is $34.50 each plus shipping.

Thanks in advance for any help.