It writes!! - Amsterdam, NL

[danilom]

Larger inside dimension of energy chain means its overall stronger and can support larger free spans.

My friend put 100 x 50mm inside diameter and it can stand on a 3m span without any problems even with 4 x 8 core cables and two water lines and 4 x 2.5sq mm spindle wire, of-course he found it second hand.

My advice is for large spans, check the documentation about free span lenght

[Fox]

Once again thanks for the quick responses guys, lightspeed !

@ SMreish
Thnx, cost as well as future expansion/add-ons was on my mind indeed ( to use same/bigger size on all three axis).

@ Danilo
Another argument, I am convinced.

Larger chain it is; hunting for second hand versions a we speak, otherwise a new Chinese equivalent.

[Fox]

Danilom,

your friend is that Paijka you are referring to or another friend ? It looks like Paijka is using much smaller in his thread ?

I just found a 103 x 25 (inside) Igus chain advertised second hand locally for cheap.
More width then I need really, but if the price is right for my meters I might take it (although Z is maybe not fitting ?).

[danilom]

No it's another friend with also a Mechmate, use larger for X Y and get some smaller for Z, but I must say, any large (over sized) piece of equipment looks really good on the machine , like a large control cabinet on Pajka's machine. Any person that looked at it was astonished, at some point we even considered a larger one. He wanted not just a machine that does its job, but also a showpiece. That's why the machine was professionally painted with fillers and sanded. The cable chain is I think inside 75 x 35 inside
Second hand parts can be somewhat helpful to lower the budged but get the once very expensive part with real quality, that's my opinion.

[Fox]

but I must say, any large (over sized) piece of equipment looks really good on the machine

Must be a male thing

[Fox]

Ps. If my eyes are not deceiving me I think Gerald used that size ( 103 x 25 (inside) Igus chain)

on his original ?

From that view and from a quick CAD sketch it looks nice, but is fouling the use of full Z height ( cable chain hitting object as it is lower then Y beams because of bending radius of 175 mm)

[Fox]

Hi, I got another question for you guys...

...would it make sense to have the machine ( once it's leveled and squared up -use some clamps for that routine- ) center the holes for the support board in the steel beam, then drill them up to size with the magnetic drill ?
Then drill two diagonal holes in the support board, align it, bolt it down, and run the hole drilling + countersunk screw routine with the machine ?

Not that I mind doing them by hand if really needed, but I was thinking.. hey, I am building a CNC machine here, which are great at repetitive work, and way more accurate then I am by hand...

Makes sense ... or not ?

[normand blais]

I would try it ,I cant see why it would not work. You might have to rig a drill instead of a router to do that .It would save time

[Fox]

I am not going to try to drill the main steel beams, I think that would lift the pinions of the rack ? Just center it ( touch it with a drill, or maybe even fit a automatic spring loaded center punch in the spindle and make the center points that way ). For the mdf I do not need to fit a drill, I'l be fine with the Spindle I imagine.

Dreams for sure, not on that point yet, still need to finish my base table and then move on to the kitchen project ;-)

[Fox]

Hey guys,

been catching up with my other work, cleaned out the destined Mechmate room re-located some stairs that we're in my way... wired some proper lighting in the room and painted all brick walls pure white ( now that makes a huuuuge difference for a pleasant working environment in a no-window room ). Waiting on last coat of paint to dry, and can then re-assemble the table somewhere this week into it's new home. Unfortunately the next week I also have to travel out of the country for business for 3 weeks end of March-April, so it will be untouched for a little longer when it's back on it's feet.

Want to pick up momentum again upon my return and get it running asap, so I am trying to order all big parts/long lead-time parts before I leave. Have spend more time studying plans and parts for the kitchen table project and have cleared most obstacles for that but have a nagging question i hope you can help me out with:

I want to wire Bipolar parallel the Deitech 86HS9801 ( in know the cons vs pros - so let's assume this is a 'fact' ).
Looking at the data at their site .. I assume this is unipolar data.

Bipolar parallel current = Unipolar current X 1.414

Which would mean 4,0 x 1.414 = 5,656 A

The leadshine DM 856 driver offers 5.6 A max (4.0 RMS). Would this driver still be safe ?

- Or should I move a step up to the DM 570 which offers a max of 7.0 @ 5.0 RMS)?

- Or.. would neither be sufficient ?

I am asking, because I can't properly judge ( first CNC ) if the RMS value is that important ( I imagine the motor will not be asking full power most of the time ) and/or if the 0,056 amp underrating of the DM 856 driver is actually an issue to worry about ? ( or can it be easily neglected like with the calculated VA power of a power supply usually being much higher the numbers people actually use... )

Thanks for any insights !

[Fox]

does anybody have an idea about the question posed above ? I am still puzzling with this issue ( electrics are not my strong point ). Thanks in advance !

[danilom]

Fox, 9801 is 4Amp motor, so its ok to use it with DM856
mine 9802 are 5Amp and if I would run them 7Amp they would surely blow up
so that "unipolar" in their table is some error as everyone else rates it as bipolar.

also we are running one machine without problems with DM856 and 5Amp 9802 motors

just give them voltage and its fine.

[Fox]

Thanks danilom, another thing off the list. Hope to drill all holes next weekend, and then flip the table. Going to order everything electrical over the next two weeks. Main deadline is to have it up and running before summer holidays, looks a long time away, but man there are a lot of little things to think about...

[Fox]

Superbusy at the dayjob the past few months, so only baby steps, but progress nevertheless....





handy helper ( in red )



on it's feet wheels.



with table frame.



detail of bolted connections ( these bolts are temporarily - dismantled later for paint and replaced )



wheels for moving it around ( wheels will mount in two positions - this is the high position, so it can load onto trailer and such, the low position will only have 5 mm between feet and floor, just enough for small movement indoor.



dowel pins ( 5mm ) to align everything nice and properly again worked like a charm..



UNP profile mounted to I beam.



under the beast



partly welded ends of I beams



holes for support board



eat your heart out mr. Eifel



straight as morningw....



like I mentioned before, the room around it leaves to be desired. At least it'll be nice and warm during the cold winters.



birds-eye trough door opening.



designed to fit ( and it did, just )



Now for the dilemma.... do I go mechmate on my rails or these 2 x 25 mm SKF rails + 4 new carts ....I basically got for next to nothing... but 3,5 meters instead of the 3,85 meter I need.



just a tad too short... damnit... they are sooo nice... but will only fit the Mechmate gantry design if I compromise/downsize on my effective cutting size (3050mm x 2050 mm) If I would do a 'commo CNC' single big beam gantry it would fit without compromise. But Mechmate parts are already lasercut and the two big grantry beams are bought, just not welded.

What would you do !?

[swatkins]

I would go with MechMate design.. Why settle for a smaller cut volume when you can have the larger size without compromising the accuracy of the machine.

[Fox]

Actually; mechmate gantry and L rails= full size cutting. OR single beam gantry with SKF 25 mm rails = full size cutting. The whole catch is the SKF rails are 350 cm long NOS (new old stock) models, so I can't buy more wagons then the 4 I have for them. I have already decided I will use a custom z, like many mechmates have with linear rails and ballscrew. So my dillema with these 3,5 meter rails is, if I buy 2 similair hiwin rails for my Y, the whole machine has linear rails and full cutting envelope if I use a single beam gantry. Or stick to the plan... and have L profiles on my x and y and linears on my z and sell the 2x3,5 meter..

[Fox]

Decided to push on MM style a few weeks ago. The cheaply bought 350 cm SKF linears are going to be stored, and I have decided to make some small adjustments to the plans for holes etc ( Hiwin and SKF etc use mostly 60 mm hole spacing) so I made my rail holes 120 mm spacing ). I can always quickly upgrade to them in the future if I want to this way.

Makes the most sense as it will get me everything in size I want, and without any major modifications or custom design ( which always costs more time then anticipated ) nor extra costs.
I think common sense kicked in and under the motto "if it aint broken-don't fix it", I want to experience first hand the results from the ground rails, as I've seen enough MM's online with good accuracy from them-but none in real life, before thinking of any modifications.

Have since then put on the support and spoil board (28 mm MDF), welded my Y car yesterday, and will weld my Gantry later this week. Big order with motors and spindle energy chains is coming in from Deitech beginning of next week. And next week I will also start on the rails. Working on Kitchen table in between. Last thing on the build list is the modified Z slide (screw and linear guides), which I am currently designing, then major constructions blocks are finished, and I need to start assembling everything and I can start on the wiring.

Still a lot to do, but slow progress.

[Fox]

Progress; Order from Deitech came in today !
A lot of money, but happy with the pile of parts.

Description and Model No. | Quantity | Unit | Price | Total Price
-----------------------------------------------------------------------------
Stepper motor 86HS9801 | 5 pcs | USD48.00 | USD240.00
Stepper driver AM882 | 5 pcs | USD65.00 | USD325.00
Timing pulley 18XL | 5 pcs | USD10.00 | USD50.00
Timing pulley 72XL | 5 pcs | USD26.00 | USD130.00
Timing belt 170XL-10mm | 10 pcs | USD3.00 USD30.00
HF spindle 3.0KW DTS-24 | 1 pc | USD476.00 | USD476.00
Spindle bracket for DTS-24 | 1 pc | USD30.00 | USD30.00
ER11 shank 1 pc | USD35.00 | USD35.00
ER11 collect chuck (1-7mm) | 7 pcs | USD6.00 | USD42.00
ER11 collect wrench 2 pcs | USD8.00 | USD16.00
ER20 collect chuck (1-13mm) | 13 pcs | USD6.00 | USD78.00
ER20 collect wrench | 2 pcs | USD8.00 | USD16.00
Energy chains 25x38 in 2 meters | 1 pc | USD26.00 | USD26.00
Energy chains 25x77 in 6 meters | 1 pc USD | 108.00 | USD108.00
FedEx Freight charge for above goods to Holland | USD300.00
----------------------------------------------------------------------------- +
Total (by bank transfer): USD1,902.00

Question on the Energy chain, when locked in it's "straight" position it does not want to lay 100 % flat but has a slight bow to it ( ends touch but middle raises off the floor ) .
Is this normal/to be expected because they pre-load them to counter any 'sag' of the weight of the cables and themselves ?
Or is this the difference in quality between a Chinese brand and for instance IGUS ?

[Surfcnc]

Hi Fox

Been waiting for someone to use these drives.

The stall detection is the big thing these bring over a std digital drive.
Can't believe I just wrote that but things do keep moving on when it comes to technology.
The alarm on the drive(s) should be wired back to an input in Mach3 to ensure an orderly stop on all axis's once a stall is detected.
While it may or may not save the piece it is working on it will save any subsequent parts, so that has to be a good thing.

Ross

[Surfcnc]

Fox

Also noticed Claudia has sent you the motors with the key ways rather than the two flats like the original Motion King Motors.
The key ways will knock out easily but remember now to just tap one grub screw into the pulley hubs rather than the normal two to bite into the single keyway slot.

Ross

[Fox]

Hi Ross,

1)
Do you have happen to have any idea/answer on my Energy Chain question ?

2)
that ( and the higher output) is the exact reason I chose those leadshine AM882 drives in the end and at the relatively small higher price offered from Claudia compared to my originals plans for the leadshine DM856 driver... I thought it was worth a shot to try this.
I'll be using EDINGCNC CPU5 - B Professional with Ethernet instead of MACH3 though but same procedure applies.

3)
I specifically ordered the keyways, I actually prefer them over grub screws as there's no risk of slipping pinions/pulleys albeit they require a bit more advanced work to pulleys and pinions.
I will do this in my gearbox to put the 18 tooth pulley on the shaft of the motor:

[Fox]

If anybody can tell me more on the energy chain 'issue' ...much appreciated !

-Another question that has been puzzling me a lot lately: I want to order my rack and pinion. I have just found a supplier called maedler who can provide pinions with induction hardened teeth only, so the rest of the pinion can still be easily modified/worked upon, while the teeth are hardened and more wear resistant, for 9,40 euro each I can't complain ( to harden standard pinions I got quoted 40 euro per pinion ). I will combine these pinions with standard racks. The pinion ( module 1 metric ) :



Research and previous tip from Gerald have learned me that the minimum metric pinion is 24 tooth for mod 1 metric ( smaller would compromise smooth running ).

I am using a 4:1 belt reduction.

My software is EdingCNC > CPU5 - B Professional

My motors are the Deitech 86HS9801

My driver are Leadshine AM882

SO.... I mix it all up into the spreadsheet Gerald provided on the subject and get this result.



I understand how the pinion size with it's pitch diameter, and the steps from the driver influences the steps needed per mm and the resolution. I also understand the influence a gearbox has ( higher torque, higher res, lower speed ) so that a higher motor speed is needed to have the same machine speed. I understand there's a direct relation between machine speed, frequency, and motor RPM.

My questions on the part I don't understand:

1)
What would be a 'happy' move speed for the MM with these specs ( I mean no use flying the thing around if it's too much stress on the machine-but quicker is better when quality does not suffer and it's not causing too much wear). I have no idea, I found sooo many different speeds on the forum, I am lost. The 9000 was the value that was already in the spreadsheet, but i think it was just there for putting something there,or is there a reasoning behind it ? If I change it to 20.000 then my motor rpm and frequency obviously increase which leads me to :

2)
With my motors; what is the max 'happy' RPM for these (not mentioned on the site - I know many people use them - can anybody enlighten me ??)

3)
what is the max 'happy' allowable Frequency ?


My goal is to find the biggest pinion ( bigger pinion = less wear = smoother running ) that still leaves me with a reliable but also fast ( within MM capabilities) move speeds. Maedler can provide pinions in 24, 25, 26, 28, 30 teeth ( and higher, but I think 30 is kind of the max that fit's nicely with standard plates ??? )



Ps.
Last question ( sorry for all the questions - I spend already 3 weeks looking for answers and can't find them):
I know Gerald based the microsteps in his spreadsheet on the Geckodrives defaults. With my drives I can toggle all kind of microstepping: "Microstep resolutions are programmable, they can be set from full-step to 102,400 steps/rev"
So I could also tweak with this parameter as well, but I assume this is something you do not really want to do too much tweaking with, and first try to get a good set up with the other parameters ?

THNX in advance !

[danilom]

My 9802 three years ago also came with key, its a good thing.

Get 26 tooth, if it proves you need more speed get 30 , if resolution get 24. Keep 26 for spares.

Using pinion harder than rack can maybe ware rack sooner if you cut a lot in one area. Be sure to check on rack hardness.

[Surfcnc]

Key ways are good agreed.

Happy maximum speed just try 10000 or 10 meters per min go even slower (like half) if you like or are feeling cautious.

The Gecko drives are set at 10 microsteps, however you have a wide range of options, so play a bit once it is running.
Initially start with a low value and then try a high value to see (hear) the difference in movement.
The Kitchen table project is a good time to do this.
As the microstepping increases the available torque decreases so there is a cost for increasing smoothness by increasing microstepping.

The minimum allowable frequency is the kernel speed the controller PC will require to reliably pulse the signals.
This is a calculated value that will for example increase as the move speed increases and or the microstep value increases.
Gerald's gear step calculator is awseome

10 Microsteps seems to be a pretty good trade off all round but I ran my Z axis at 16 microsteps for ages and nothing bad happened.

The USBCNC software is good stuff, just finished a test of it myself.
Your board is capable of pulsing at 125KHz so you are well within the abilities of the board to provide an adequate pulse stream in your speed range.
Also note that the pulse generator is on your board so you have the benefit of a hardware pulse generator over the Mach3 software pulse generation.
You will notice that the toolpath display is unaffected by playing around with it during the machine operation, unlike Danilo and myself on Mach3 with the smoothstepper.

Energy chain - don't worry those cables are heavy and most of the MM chains end up sagging a little esp on the X axis.

Ross

[Fox]

@ Dainlo; thanks for your advice, beside common logic ( it makes sense to me to do take the middle and work up and down if I can't work it out ) but is there actually a calculated theory behind it ( do you know the max hapy motorspeed ? ), or more a hands-on trail and error approach based on your experience ? Because otherwise you could also take 25 tooth or 28 tooth just the same ( as long as I increase the microstepping to get the resolution I want, and I do not exceed the max motorspeed )?

@ Ross
- ok I will try to stay around the 10 meter per minute for starters.

- ok, will play around a bit with teh micorstepping ( was already planning to do this - that's why I bought them - but your values help for staring me somewhere)

- I now understand the Frequency a bit better, and in USB CNC - now named EdingCNC there's only an option to set MAX Frequency. I read in the manual that this is done, because some drivers will not be able to run higher input frequencies. The Maximum - MaxFrequency is the 125KHz of my board, and my leadshine driver states in the manual it can accept up to 200KHz max input Frequency. The Eding CNC board differs from Mach 3 I think with it's on board processor, so it does not rely on the PC processor connected to it for the pulses ( which can be the limiting factor with the parallel port if I understand correctly).......So........ is my conclusion correct that I can ignore the Minpulse rate from Geralds spreadsheet unless it becomes a value higher/close to the max 125 Khz value ??

Cool to read you also have been playing around with the demo. I have heard/read a lot of good stories on EdingCNC and seen it function on professional machines, but the Mach3 user database is currently a million times bigger. Most people I see using it now are Dutch. But other then that I agree with all the advantages you state, that's why I chose it over Mach3.


Both your advises taken into the spreadsheet I get this result:



I think I will start with this situ and then play around a bit, when it's up and running.

[danilom]

Aim for around 20.000 mm /min rapids (thats around 800 IPM)

Microstepping can not improve resolution, just smoothness which will you have enough at 10 microsteps

smaller pinion can affect resolution.

What is it you want to achieve. "max happy motorspeed" what is that? Under no load you should be able to spin at 1000 rpm. Depending on the pinion it will produce certain feedrate.

Question is what FEEDRATE you want? you can use any pinion and limit the feedrate so you stepper spins reliably if you don't care about feedrate.

[Fox]

Hi Danilo,

Thank you for your comments, but I must admit I am getting more confused.

Simply put: what I am aiming for is my MechMate performing at it's best capacities ( in speed and accuracy ) when cutting plastics and aluminium, without over stressing it (reliability). I assume it's what we all aiming for ( although some might be more into speed then accuracy )

Working hard is ok, that's what it needs to do,without breaking, missing steps or loosing accuracy because components get too much stress. My feedrates will depend on this and the materials imo.

Maybe I am over analyzing, but everything is quickly tunable without cost, except for pinions. These need to be then bought in a different size, machined and replaced on the machine. The total of that will not be the end of the world, I just thought to properly aim before I shoot the first time.

So tried to make a prediction with the calculator on what would work best. Then things came up I did not know: max happy speed for MechMate to work reliable ( because of the design /structure ), max motor speed, max/best micro stepping settings.

So all my questions and then your comments on those followed and here we are with more questions assumptions:

- Do I understand your 20.000 mm/2 meter minute in "rapids" = means straight line full speed ? ) Is that a general cutting speed ( I know it also depends on materials and bits) or a Jog Speed ? I see this mechmate is cutting the spoilboard at 1150 IPM = 29210 mm/minute (!) which is extreme I think, but i also see much more considerate speeds.

- Driver Microsteps did affect resolution in the spreadsheet but I did not read correctly it is microstep resolution that is affected, I see now. I understand this is different from the actual resolution ? I thought it meant with 1 microstep the machine would travel 0,006 mm ? And I though the lower the number the better your accuracy becomes, and that one can influence it with microstep settings or pinion size ? Am I making a fundamental thinking mistake here?

- Happy motor speed = I want my motor to be happy at the best max speed of my machine. Meaning a stepper motor in general maxes out at about 1000-1200 rpm I found somewhere on google, because after that torque becomes to low to be useful ? But it was also written that some steppers might make it to 1000 rpm, but will not be useful at all anymore. So my thinking was; does anybody know the maximum RPM for my steppers to be still useful. Because then I could fill in the the other parameters in the spreadsheet based on that ?

- Feedrate I want: the best feedrate possible within the MM capabilities/my config.

Anyway .... some scenarios at 20.000 mm/second with either 10 microsteps or 16 microsteps all give stepper rpm around 1000 rpm, so that would be the max speed If I follow my google assumptions, if I want to go faster I would need bigger pinions ?? :

[danilom]

20.000 mm/min rapid positioning G0 or jog at 100%
for cutting you will use much less, leveling the spoilboard is easy on the machine as it only peels a thin skin... just to level it, usualy 0.5-1mm

microstep only increases Steps per mm, that is the number of STEP signals needed for motor to move the machine 1mm, thats theory. In a real world you will have no less than 0.05mm positional accuracy or repeatability. Consider also the non linearity of a rack, even ballscrews have their accuracy for a given lenght.

[KenC]

Nobody know or at least nobody that I know of took the time to plot their own Torque Vs Speed curve at the Voltage & microstepping condition...

you are right in saying its useless knowing the "happy speed" as tuning is free & trivial.

In real life, microsteps doesn't increase resolution as far as the number said. ~8 is about the best before you hit the point of diminishing return. so many just use 10. The real resolution improvement comes in the form of mechanical speed reduction. The million dollar question is: are you sure you realistically expect your wood or plastic's thermal expansion is below 0.05mm?
Than again, when you step your motor speed down, especially with high ratio step-down, you are effectively running your motor into the low torque region of its Torque-Speed graph... & if you are unlucky (which real world happens a lot ), you may end up with lesser torque than w/o speed reduction... tough...

[Surfcnc]

Fox

Correct on the step frequency as long as your gear step calculator says you are under 125Hz you are good to go.
In practice you will never get near that frequency with your steppers and belt drives.

Ross