Motor upgrade

I'm still waiting for news. I don't have a date yet.

peterg1000, could be, but it makes it quite sensitive do get the "proper adjustment". While it might seem trivial to you, it seems like it isn't for most people. There's also a lot of people who will be very happy not to have to deal with the belt ever again.

Sorry to disagree here - if the machine is properly adjusted there is adequate power in the standard motors. I can achieve slew rates of over 3000mm/min on all axes on my 420/2.

I actually measured the torque required to move the Y axis once adjusted, and found it to be less than 10% of the rated torque of the stepper.

I set the tension on the rails/roller to produce the recommended 1kg (10nm) required to move it.
The X axis rail on the 840 is twice the weight of that on the 420 so the Y axis is under more strain to get it to move, and stepper loose torque the faster they go.

The standard Y axis stepper can only pull its maximum torque up to 300RPM (900mm/min) and looses about 25% of its torque at 1000RPM (3000mm/min) and it rapidly drops off from there to the point it doesn't have enough torque to turn its own shaft.

Having two steppers on the Y axis will reduce the torque required by the motor and make it less likely to stall.

I'm still waiting for news. I don't have a date yet.

peterg1000, could be, but it makes it quite sensitive do get the "proper adjustment". While it might seem trivial to you, it seems like it isn't for most people. There's also a lot of people who will be very happy not to have to deal with the belt ever again.

I second that. Get rid of the belt. I've already replaced it once and the replacement is starting to look a bit strained and need to be replaced again. Hopefully the dual stepper upgrade is available before this belt wears out.

Has anybody measured the stiffness of a D.840/v2? The spec states 0.1 - 0.14mm for a load of 20N. I can hardly believe this can be reached with stock steppers, since you have to put some tension on the rollers. Especially when X and Y are positioned in their axis' center positions. Furthermore, it seems the X extrusion is quite likely to twist under load.

Sebastian

@hasew I do recall when assembling my X axis that I has to have a couple of attempts because the X axis rail which is over 600mm long it had twisted. The left side was perfect but the right side was causing ridges in the bottom of pocket cuts. By loosening the right side and giving it a light twist, it is OK now.

Quick questions:

> any idea when the kit will be sold ? What will this kit solve ?
> saw the motors are only 0,5 Nm of torque when competitors (like X-Carve) are around 2 Nm, which is 4 time more...Quite huge gap ! Does it mean the D-Series are 4 times less able to cut ?

The Perfomance Kit is availible now at https://shop.stepcraft-systems.com/electronics

Hello, this update is a bit disappointing, I was hoping to have an improved motor for each axle.

@skynet do you know the max motor output for each driver on the new control board?

Has anyone looked for higher performance NEMA 17 engines and controlled them with an aftermarket controller such as a Duet3D? The only thing that puts me off this is not being able to use it with UCCNC and having to program the Duet myself, although it doesnt seem rocket science....

I think that would eliminate many skipping problems due to slight mechanical interference.
Im fed up with EVERYTHING effecting the performance.
Too cold - Skips steps
Wrong grease - Skips steps
Slightly dusty - Skips steps
Anything but a brand new cutter - Skips steps.

Many Thanks.

AFAIK, 2.8A per driver, but to squeeze that much out of it, you'd probably need a power supply with a few more amperes.

Don't be disappointed with the new motors, the Y axis performance is vastly superior to the original. They don't have as much torque, but they move much better, so I'm assuming the torque curves are way better in the higher rpm range.

There are people who have done lots of mods, join the facebook Stepcraft group, you can see some of them there. Even people using Nema 23 motors.

I think if you're having so many issues with skipping steps, you must not be doing the setup correctly, I can understand the issues with the cold, but otherwise, it seems like you can improve the performance by just adjusting. I've made a video about it, maybe it helps: https://www.youtube.com/watch?v=QnxRD5jeIOY

Thanks!!

Im not dissapointed in the motors, just that they arnt upgraded on each axis, as thats what I was looking at doing a few months ago, but was waiting for this upgrade.
Saying that, if it can produce 2.8A per driver, then uprated NEMA17's are pretty cheap to "add on" to the upgrde package.

Rory has sent me some newer videos that he has made, since I first bought my machine, and although he is setting up on a smaller machine, he looks to be turning the X axis screw by just rolling his thumb over it, I can just about turn mine between my finger and thumb with the motor connected.
Im going to have another go at setting up in the coming weeks.

Hi All

Hope this is the correct thread, seems so. I have recently put the Y axis upagrade, which lets be honest should have come with the machine, however running some basic 1.6mm cuts at 22mm/sec with a 2mm end mill in Mdf yesterday saw the X stalling and snapping cutters..... The X axis is perfectly tuned as well as me adding the tightening lead screw nut to get rid of the mechanical backlash, which I still cannot understand is possible out of the box!

I spend hours looking at the specs of the old Y stepper and the current X stepper. They old Y has double the holding torque of the current X stepper and only draws 1.8A v 1.4A. The drivers on the Performance boards look to be all the same driving x2 2A steppers on the Y, I don't see why it cannot be reassigned with the old Y replacing the X stepper??

Anyone got thoughts on this?

Stepcraft V2/840 /w performance kit

Right, so after much research and deliberation I decided this mod has to be done, without it, I cannot trust my machine. I checked the thermal temps of the Y v X drivers and the X was already lower after the motor swop, including the steppers. I tested the torque and what can I say, double! I decided some cooling should be in order anyway so designed the below which covers 80% top of board and c 20% below, all is running cool and super strong.

I can part with STL`s or completed parts for a small price

G

"Hope this is the correct thread, seems so. I have recently put the Y axis upagrade, which lets be honest should have come with the machine, however running some basic 1.6mm cuts at 22mm/sec with a 2mm end mill in Mdf yesterday saw the X stalling and snapping cutters..... The X axis is perfectly tuned as well as me adding the tightening lead screw nut to get rid of the mechanical backlash, which I still cannot understand is possible out of the box!"
Hi Theg,
In my honest opinion based upon my cnc professional milling experience 22mm/sec(1320mm /min) is far too fast a feed rate speed for great results with your stepcraft machine.
I am used to working in mm/min,.
My sc 400 only moves at 1800 mm/min rapid, so I would not even think about going anywhere near that speed under load.
Max feed rate I have machined at is 800mm/min , 3mm hss slot drill, 1mm depth of cut, wood( fir tree , pine etc.)
I have had no problems to date with that feed rate.
If what you do with your stepcraft machine is for a hobby, then time is not money, its enjoyment.

I don't disagree with you, coming from a multicam mt with a 9hp motor requires massive adjustment. That said the X axis stall on the 840 is simply unacceptable. My mod seems to be working well and have about 200hrs under the belt with that mod now which has seen 0 missed steps and with a tensioned lead screw nut you take away the backlash risk which exacerbates the need to compensate with a slower cut, software compensation is a non starter for me. that said, its the machine flex and profile that is the next happy medium to find. I have found the X-Axis rollers to be the biggest culprit here, the tension screws come loose and allow play which invariably causes bite enough to cause play in the machine, at that point its over 🙂 most of this stems from trying to cut some wheel spacers I made for a friend, so may unnecessary variables with the machine, but mostly the X axis roller! the end results was hard fought, but tolerances we spot on

[quote="Hurcokid",
In my honest opinion based upon my cnc professional milling experience 22mm/sec(1320mm /min) is far too fast a feed rate speed for great results with your stepcraft machine.
I am used to working in mm/min,.
My sc 400 only moves at 1800 mm/min rapid, so I would not even think about going anywhere near that speed under load.

I have a well tuned (but not perfectly tuned) Stepcraft 2/840 and have achieved a sustainable, reliable feed rate on XY axes of 2,500 mm/min for wood cutting at depths per pass up to 1.5 mm for several hours at a time. I believe that I could reliably run at 2,750 rpm when cutting wood. I have tried 3,000 mm/mm and my x axis will bind up.

I run considerably slower on rigid materials such as plastic, around 800-1200 mm/min.

Doug