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#1
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MechMate Project in Johore, Malaysia.
Hi,
I've registered meself into this forum quite a long time ago, and now ready to get serious. Someone decided to donate around US$2000 for me to build one. This thread will be a journal of my build, as i collect information and decide on the parts and where to buy, squeezing the options to fit the budget. I don't worry much about the frame, as iron and steel is relatively quite cheap here. metal stuffs will be definitely no more than US$1000. A friend estimates that it would costs somewhere around US$300-US$500 (~MYR1100). I'm quite alien to engineering components like bearings, gas spring, stepper motor, drivers etc. Don't know how much it'll cost, already searched for local suppliers, just haven't got time to ask for their prices yet. I hope you guys can help and guide me in choosing the parts. I feel happy to be able to join this big and happy family |
#2
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Welcome Nikonauts!
There is a small chance I will be visiting Malaysia next year . . . . |
#3
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aww... nice. PM me if it's confirmed especially if you'll be near the peninsular south (nearby singapore).
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#4
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Selamat Datang Nikonauts!
Its great to see all the different people from around the world here. |
#5
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Terima Kasih Heath.
I'm still having problem deciding on the electronics to use. initially these are the setups i have in mind : Driver : G203V From : GeckoDrive Price : $147 x 4 units = $588 Output : 7A 80VDC 10-Microstep Motor : KL34H295-43-8B From : KelingInc Size : Nema34 Price : $105 x 4 = $420 Spec : 906Oz 6.1A 2.1V PSU : KL-5413 From : KelingInc Spec : 54VDC/13A Price : $139 BOB : C10 Bidirectional Breakout Board From : KelingInc Price : $25.49 Total : $588 + $420 + $139 +$25.49 = $1172.49 Shipping charges are not included. Oops. That's more than i can afford. Never thought just by needing a bigger motor i'd need bigger everything. Previously, i was only planning to make small machine with smaller motors, like 380Oz-In. Can anyone comment on setup below : Motor : FL86STH118-4208 Provider : Motion Control Voltage: 3.78V Current (phase): 4.2A Resistance (Phase): 0.9Ohm Inductance (Phase): 6mH Holding Torque: 8.53Nm (1200 Oz-In) Length: 118mm Frame: NEMA34 Price : $83.10 x 4 = $332.38 savings = $420 - $332.38 = $87.62 Driver : MSD542 microstepping driver Provider : Motion Control Output : Supply voltage up to +50VDC, current output up to 4.2A peak Features : Optically isolated input signals, pulse frequency up to 400 KHz Price : $70.50 x 4 = $282.00 Savings = $588 - $282.00 = $306.00 PSU : PS705 Provider : Motion Control Output Voltage : 75V DC at 0A & 68V DC at 5A Output Power : 340W (Continuous) Cost : $62.80 Savings : $139 - $63 = $56.00 Total Cost = $62.8 + $282 + $332.38 = $677.18 Total savings = $56 + $306 + $87.62 = $449.62 Is 1200 OzIn too big? The next smaller motor they have is a 400 OzIn, too small. I wish Gecko is going to have another Sale around this time. If they're selling 203v for $100, i'm gonna grab them for sure. please advise.... |
#6
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1,200 oz*in motors are too large for Gecko stepper drivers. The 400 oz*in motor would be better, especially if attached to a 3.6:1 belt-drive transmission. 3.6 X 400 oz*in = 1,440 oz*in. In the motor section, Gerald posted a caution from Mariss about using large motors. (Sorry, but I just realized that I don't know how to link to a specific post.) Perhaps the MSD542 is better suited for driving large motors, but from my understanding, large motors have much greater problems with harmonics (excessive vibration at lower speeds). The Gecko stepper drivers have a motor tuning adjustment, but, even with the adjustment, they are not perfectly compatible with large motors.
Also, that 5A power supply is underrated for 4 motors. Each motor can pull 4.2A, so a 12A to 16A power supply would be better suited (depending on how hard you plan on driving your machine). Buying a large (amperage) power supply is cheap, compared to not being able to do the work that you built the machine to do. Last edited by Richards; Sun 14 December 2008 at 06:17.. |
#7
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Nikonauts, I don't understand why you want to buy motors from England or America when their motors are made in Asia and you are in Asia?
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#8
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Nikonauts , you can email claudia_xia@hotmail.com for steppers and drives and spindles, I am planning to get a Asian spindle myself from them. They ship out of HongKong and you may get everything you need from them - they even list timing pulleys on their website - however I dont know the quality of the stuff they supply.
Their website is http://www.driver-motor.com/ My best to you in your build! RGDS Irfan |
#9
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Got quotations from motionking, $50 for 34HS9801. $200 for 4 units, $154 for S&H. $354 total.
wonder if their $80 driver worth buying. My brother agreed to make BoB & PSU for me... It's all down to driver now.... anyone have any good luck with cheap driver out there? I'll buy gecko once the machine made itself enough money..... |
#10
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Is Gecko G250/G251 good enough?
It's cheaper than MotionKing drivers, plus it has mid-band resonance compensating feature. Good? no good? |
#11
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Guys,
a motionking motor 34HS9801 has the below characteristics : Unipolar Rated Current (A) : 4.0 Phase Resistance (ohm) : 0.98 Phase Inductance (mH) : 4.1 I've read too much in too little time, confused already. how much is the inductance when the motor is wired half-coil? What's the rated current then? Will it then match "perfectly" Gecko G540 inductance requirement (2.5mH-3.0mH)? Will it do fine when supplied with 50V? With G540 i don't have to trouble my brother to make a BoB anymore.... |
#12
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The MotionKing web page states that the listed specifications are for unipolar (half-coil). That means that inductance for bipolar series would be 4 X 4.1 mH or 16.4 mH. The rated current for bipolar series would be (1/SQRT(2)) X 4, or, 2.8A.
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#13
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Nikonauts, the G540 with its G250 drives is not going to manage slow turning direct drive motors to their full capacity.
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#14
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Ok ordered stepper motor and driver.
Driver will arrive tomorrow. Stepper will start shipping on the 5th due to long holiday in China. Have sent drawings of V-Roller, ecc. bushings etc. to machine shop. Got quote and will see them tomorrow to change material spec. to squeeze a bit more on the price. Sent quotation request to local metal shop, expecting to get from them tomorrow. Tomorrow will send drawings to laser shop. It will be a very busy day tomorrow. |
#15
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I see from http://www.cnczone.com/forums/showthread.php?p=544166 that you will not be building a MechMate at this stage?
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#16
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Quote:
Marcus confirmed that 34HS9801 4.1mH inductance is good for the G540. We'll see how it works. I find that many people don't push their motor to the limit. They always go below the rated amperage/voltage of their motor. From 65V to 50V, 4.0A to 3.5A i think is comfortable. Well, that's more like what i "guesstimate" as i am inexperienced. While it might be within the "lazy range" of the motor, it is for sure squeezing the max out of the driver, but hey, that's why gecko is best known for. I'll give it a try. If it fails, it's my bad. If it works, it's good news for people within limited budget. DIY CNC is about bringing technology and ability to fabricate to individuals with less financial resource. It's about democratization of technology. It's a shame that a solid mechanical like MechMate is out of reach of these people because it must run on expensive electronics. I read on Make magazine on MIT projects of bringing cheap CNC and 3D Scanning & Printing to enterprising people of the 3rd world. I think the same principle should be close to the heart of MechMate, "coppulating" beauty of technology/invention with people's power. Mechmate, while still out of affordability of average individuals (to splash 4 months of income into a hobby) it's a great help for small businesses or aspiring entrepreneurs to bootstrap to a higher level. US$15k-$20k imported full size machine is a lot especially if they are struggling to compete with well established contemporaries. We'll see how this one goes. I definitely gonna need advice from a pro like you Gerald, but if it doesn't work then the blame is all on me and i hope you won't stop giving advise because i go against this one. To muslims : Happy New Hijriah Year, to chinese/vietnamese : Happy Lunar New Year, to everyone else : Happy Gregorian New Year. We're celebrating 3 new year within 1 month here, back to back. |
#17
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Quote:
When i find that hardened chrome shaft is cheaper here than in the net, i was thinking that i might make my own design using end supported 20mm shaft. Plus, with the emphasize towards the use of G203V and Geared OM Motor puts me away from MechMate. Later it occured to me that 20mm shaft will deflect badly when spanned 1600mm (according to online calculator result, and also to postings in CNCzone). And only then i realise that MechMate is the cheaper way to build a 4x4 or bigger machine. When it discard the use of ballscrew and fancy linear motion method it's economic and scalable. Today i realise another thing, when you have to buy steel in stock form, it costs the same to build 4x4 as to if you build a 4x8, only floor space constrain tells you either it's gonna be 4x4 or 4x8. (well, you have to add just a little bit more, it's virtually negligible compared to the gained benefit). At first i was bent on building mechmate, later when i worry about the electronics cost, i was thinking about building an own design. when my own design go against me, i'm now 70% leaned towards mechmate. i could, of course use diy linear motion (read: skate bearing) on my own design, but if possible i need a presentable design. my goal is to build machine for my people. i want them to embrace cnc so they could be competitive, for that it has to be presentable and affordable. tomorrow i'll collect quotations from laser/plasma shop, metalshop, machineshop and at night i'll be back to kitchen table. Hopefully not gonna go back to drawing board. haven't surveyed the price of pulley and belt, i'm also weighing using belt to drive the machine, not just as a mean of reduction gearing. |
#18
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It's 2016!
After 7 years, I'm reviving the project. Took all the parts already purchased in 2008 out of my closet, still look brand new. Some bearings have a bit of rust, going to ditch that. My EI core transformer can't be found. Never mind, hate it's loud vibration anyway. Old components : Stepper - MotionKing 34HS9801 x 4 units. Driver - Gecko G540 x 1 unit. E-stop, limit switches. Capacitor - 15000uF 100VDc Bridge Rectifier - KBPC3510 Ordered new :
To be ordered after CNY holiday :
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#19
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Kool.
Even I didn't take that long. |
#20
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good luck,with the project, i hope you share pictures with us,it would be interresting
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#21
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Surely, yes... I will.
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#22
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Received gas struts and transformer from RS.
It's bigger than I imagined. I know they're 880mm long (400mm stroke), and it'll protrude vertically quite tall, but didn't imagined it would be that tall and the cylinder that thick. It'sold in pairs. Wondering should I sell one, or just keep it as spare. The transformer is on the table, black cylinder with orange label. I thought the casing can be opened, but seems like it's permanently sealed. Last edited by Nikonauts; Sun 14 February 2016 at 03:48.. |
#23
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If they work keep it as a spare.
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#24
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How long yours last?
I read somewhere Gerald said he expect them to last a year, but his last i think 2 or 3 years. |
#25
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So far 2 years and I have a spare as well which I compress once-in-a-while. I store it shaft down cylinder up.
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#26
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I got about 3 years on my original with about 20 hrs of use a week
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#27
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Thanks Sean and Tom. I will keep the extra.
Need one more help... need to figure out specs for reduction belts/pulleys. I think I'm going with the GT2/GT3 profile as it's designed for high torque application and very low backlash compares to it's predecessor HTD, and other belt profile. However I can't figure out how to determine the minimum pitch size and belt width. I've searched the forum to see how others built their reduction belt, but mostly it's about the plate design, shaft and bearings. Any help on how to approach this? Last edited by Nikonauts; Mon 15 February 2016 at 00:27.. |
#28
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I use an XL belt .20 pitch (1/5 inch), to me it seemed to have the most available pulley options at the time. I'm set-up with 3.6:1 reduction, I've never broke a belt (available in kevlar) and I've never jumped teeth. I can't remember what the other most common metric belt is (been a while)
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#29
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0.2" (5mm) pitch size sounds just right, Tom.
May I know the width? And do you notice any backlash? |
#30
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