[asuratman]

Mariss,
Why not developing chip to make existing drive no need so many additional board. I have 3 ea gecko 320, I need many parts to make it work. It take long time, If you can make it simple with new chip, it will be good. If you go for $29 just to compete with china, I am just standing as viewer. I have no time to make it work.

[Mariss Freimanis]

WOW, for the cost of what I paid for lini-stepper kits (that are still half built), I coud be in a quality low power drive? Bring it on!

So, being a MORE POWER kind of guy, what sort of interlocks will be designed in to keep me from trying to push 5A through these if I added heat sinks? And better yet, how can I hack around them,? :-) A $30 drive I can hack for a couple more dollars into a 5A drive would have me tip toeing through the tulips.

I believe there is a project on the back burner looking for three of these.

The "interlocks" are economic in nature. The drive is being designed with circuit traces, current-sense resistors, heatsinking, reference scaling, voltage regulators and power section components scaled to the requirements of the design; reliable operation at 3A and 50VDC maximum. Anything in excess is a waste of the customer's money. A "hack" will only eat into the prudent reserve built into the design.

Mariss

[dertsap]

a three amp driver at that price would be great ,anything in comparison in price is generally a 2amp max piece of crap noone know where it came from ,ebay is flooded with the stuff

as far as hurting the competition goes ,who cares ! instead of buying trash for 29 bucks i can actually buy quality . yeh suppose that will hurt the competition , oh well screw em !

[Larken]

Maris
I don't know how you can make a drive with 72 parts for under $6.
even at 1000 piece qty.

$4.00 8 x IRF540's @ 0.50 each
$1.00 your control chip
$5.00 4 x IR2104 drivers (quoted by arrow and Digikey @ 1000 price)
$$ Support chips
$$ Capacitors , resistors, led, header
$$?? That big connector
$$ 4 layer PCB
-------------------------------------
Lots $$

And if you have to buy in huge qty's to get that price lower, you are really trying to pinch penny's to keep the price super low.

On my Larken Viper 200 servo drive, the cost of the parts is $60 and that doesn't include heatsink, assembly or testing.

Generating the Cheap Drive occurred while sitting in our hot-tub last Thursday evening, enjoying good conversation and a bottle of fine wine.

Your so romantic. If i was in a hot tub with good (female) company and a bottle of wine, stepper drives would be the last thing on my mind !!

Larry kenny

[dannystooblue]

I would be interested, I would as well be interested in what it would cost to get the same in a 5 or 6amp as well. There are alot of stepper drives under 3amp out there in an affordible range but anything over 3 starts to really cost. I have gecko products and I appreciate the quality and more I appreciate the support. Mariss actually took a good amout of time to explain how to set up his drives and how to get the most from my servos. Thanks to him my machine really has the power it needs because I was on the wrong track.



Danny

[Mike Nash]

This thread is a hoot!

A US manufacturer decides to cut costs AND PASS THE SAVINGS ON TO THE CUSTOMER, and meets with opposition! Why, that's not the American Way. That'll hurt the poor guy buying from Chinese producers and just trying to make a living (while undercutting US manufacturers' pricing.)

Walmart offers (slightly) lower prices by "beating up" on their suppliers. Some of the suppliers cut costs by giving Walmart an inferior product compared what they're producing for other retailers. Ever wonder why name brand tires bought at Walmart or Sam's Club won't stay round? How about those $58 dollar mountain bikes you can't steer because the front tire hits your feet as you pedal? Or the throw rugs that are so thin, with the latex backing that prefers to stick to your floor rather than the rug? And if they're the "low price leader", why is it I find the same products that they sell for $5-6 for a buck at the dollar stores? Where's that other $4-5 going when the dollar stores can make a profit selling at a buck?

I personally am very impressed by Mariss's business model. He's not out to "kill the competition" nor "get his while the getting's good". I'll bet he sleeps pretty well at night. And if he makes a drive OEMs will drool over available to hobbyists like myself at a very favorable price, who am I to complain?

One further note. I'm not a "Buy American at all costs" individual. When American manufacturers offer good products at good prices, sure I'll buy. But I buy lots of Chinese and Indian made products too.

[jseiler]

I think input isolation would be worth the cost to most buyers in that they could avoid a breakout board. Just a thought. I can't believe anyone would gripe about a nice cheap 3A drive. I just got done buying a used PRT shopbot box for 300 + shipping that will only drive 1.5-2A at less than 4000 pps. This insures I won't see more than 1 ips at 1/2 step on a K2cnc with .1" pitch screws. For the same kind of money, I could have gotten mach3, 3 drive boards, a breakout board and a surplus power supply and spin 2.5 ips or more pretty easily. Or Kreutz's new boards with a 4th axis.

John

[Mariss Freimanis]

Larken,

It's far less expensive than that:

8 30A 60V 0.039 Ohm D-PAK MOSFETs @ 0.19 each, $1.52
4 IRS2104 half-bridge drivers @ 0.45 each, $1.80
1 4-layer PCB 1.25" by 1.625" @ 0.39 each, $0.39
1 XC2C32A CPLD @ 0.95 each, $0.95
2 SOIC-14 quad linears @ 0.12 each, $0.24
2 1206 current sense resistors @ 0.04 each, $0.08
6 SOT-23 diodes and transistors @ 0.03 each, $0.18
1 Al electrolytic cap @ 0.27 each, $0.27
47 0603 resistors @ 0.003 each, $0.15
21 0603 capacitors @ 0.01 each, $0.21

Add it all up and you pay $5.79 for your shopping spree. That leaves a whole $0.21 left to splurge on God knows what. Maybe a nifty connector and an LED. The total does leave out the 12V regulator which is yet to be determined, it will almost certainly be a "roll your own" circuit.

You can say we squeeze every penny from a design; I prefer to say we squeeze every ounce of performance from each penny. It also helps to use major parts distributors. We spent over a millon dollars with our distributors last year; as an example we purchased 240,000 IRF540Ns alone. This makes it possible to get advantageous quantity price breaks for new product components. They know the quantities will rapidly ramp up in the future.

Mariss

[RotarySMP]

Interesting discussion. As technology marches fwd (and in electronics it does tend to), new things become possible.

Routerman, Marriss has determined that microelectronic hardware has progressed sufficiently since 1998 to enable a 3A 50V stepper drive to be commercially viable at about $30. These days it is differcult to extinguish knowledge. Someone is going to build 3A 50V drives for $30, and in a couple of years, those drives will get undercut by someone using the the next technology to make better drives for $20.

We the user will get to profit from $30 drives, because they will get made. Would you rather see someone profit from this who has contributed greatly to home CNC, who has demonstrated a strong track record in honest business practice and fairness to customers and employee's? Who do you want to deal with?

I would think the hardest hit from such drives would be Xylotex. They made the market at the last price performance point for 2-3A drives. It will be exciting to see what solid competition leads them to design.

Marriss, you mention that the interface will not be screw connectors, will it be DIL pinheads?

Maybe some of the current low end drive kit manufacturers will see the market opportunity for developing interface boards, motors with appropriate connectors etc.

[tauntdesigns]

I have 2 motors that are 2.8amps and 1 that is 3.05amps, so yes, I could use this product at 3.0amps.

I can a see someone making a 3 or 4 axis board with geckos mounted and a 25 pin connector on it and little connectors for the motors. Could make for a smaller electronic enclosure.

Thinking out load,
Jack

[epineh]

Well the reason I think Mariss would be crazy for not pursuing this are as follows :

Electronics are cheap, as he states 6.00 in parts for this drive, with a little buying power.

People are "tech'ing up" I don't claim to be any kind of EE but if I needed a PCB done right now I could produce a double sided board with 10mil traces (I believe that is 10thou...you would need magnification or SMD curve oven to solder) within about 10 minutes.

My version of a servo drive based on the Elm Chan servo drive cost me about $20.00 (Au) to build, without any buying power, I built the first ones for 24V servo's, and rate them at 25 amps, but could easily be changed to 60V and about 10 amps with a little work.

I am sure I am not the only person in the world with these capabilities, I MAY even concede that some may have a little more knowledge than me (T.I.C)

Now I am hardly going to be any competition for Gecko, I do not intend on selling a single drive, my reasons for all of my research, prototyping, testing blah blah blah is purely for the enjoyment of learning something new, and keeping the 'ol grey matter in shape for later in life. I am sure that there are people that ARE interested in pursuing sales and with the sheer processing power of FPGA's and CPLD's that have flooded the market it is only a matter of time that servo/stepper drives start making advances in software and begin to move away the constraints of hardware for a competitive edge and more towards programming.

IMHO any drive manufacturer that wants to sit on the fence and ignore technology that is advancing at an exponential rate is going to be swept away in the digital flood.

Russell.

[Larken]

Marris, You price on the irs2104 was years ago, they have gone up a lot lately, probably because the US$ doesn't have buying power anymore.

Digi-Key Part Number IRS2104STRPBFTR-ND
Manufacturer Part Number IRS2104STRPBF
Description IC DRVR HALF-BRIDGE SHTDN 8-SOIC

Unit Price Price Break
1.37700 2,500
1.32600 5,000
1.27500 10,000
All prices are in US dollars.

What distributer do you get your from?

-----------------------------------------------

Also,
On your new board, you should make it a card-edge mount type that plugs into a little mother board, like Rutex did on their 990's

Then someone could make a small motherboard with maybe powersupply and breakout board built in. Just a though.

Larry K

[ger21]

Marris, You price on the irs2104 was years ago, they have gone up a lot lately, probably because the US$ doesn't have buying power anymore.

I would think that if he sold $5,000,000 worth of drives last year (based on his $1,000,000 worth of components) that he knows what he pays for them.

[joecnc2006]

Also,
On your new board, you should make it a card-edge mount type that plugs into a little mother board, like Rutex did on their 990's

Then someone could make a small motherboard with maybe powersupply and breakout board built in. Just a though.

Larry K

Hello ! ! !

http://www.pmdx.com/PMDX-131/

[Larken]

I would think that if he sold $5,000,000 worth of drives last year (based on his $1,000,000 worth of components) that he knows what he pays for them.

I don't think even Marris can control the US economy. The US$ has fallen 30% in the past 3 years. I used to pay $0.50 each too.

The price has gone up.

Hello ! ! !
http://www.pmdx.com/PMDX-131/
Reply With Quote

Hello what ??? Thats not a card edge setup !

[Xerxes]

Larry, if you buy in very large volumes, you probably don't have to pay list prices.

But maybe Mariss should put this drive design on IC and just sell millions of them for $3-5 :-)

[dertsap]

anyone who is smart in business knows the price is always to be negotiated when buying bulk , list price means nothing if it results in a lost sale

[jseiler]

another crazy idea. I noticed a few people where interested in running higher currents on the cheaper drives. Could one instead use two drivers running one motor? 1 drive running one set of coils (a-b-half coil) and another driver running the other set (c-d-half coil) on the same motor, effectively doubling the drive capability?

The only real problem I see is the if the PWM current limiting starts to induce ugly currents between the windings...but it might not matter.

John

[CoAMarcus]

anyone who is smart in business knows the price is always to be negotiated when buying bulk , list price means nothing if it results in a lost sale

Well, as the one who does the buying and negotiating with the parts distributors, I can tell you that it really does help to negotiate. I know that the list price on IRF540NPBF on the Digi-Key website says 80 cents for 1000 quantity, but when you buy in bulk you can get it for 34 cents apiece. Buying in bulk will be our way of pushing the price below $6 for parts, which should be doable. Right after I finish typing this I am going to be calling some suppliers to make sure that we can indeed keep the cost as low as we like.

[CountZero]

Marcus, Mariss;

Thanks for sharing so much details about your design, it is impressive how much you have squeezed in to that little CPLD! Hope we will see the finished product soon. Good luck.

/Daniel