okay great I'll start working on that but if my plate is 20mm thick, the pocket depth would eat up the shaft length, so is it acceptable to have the pocket area maybe 10mm thick only for example?Quote:
Originally Posted by routercnc
Printable View
okay great I'll start working on that but if my plate is 20mm thick, the pocket depth would eat up the shaft length, so is it acceptable to have the pocket area maybe 10mm thick only for example?Quote:
Originally Posted by routercnc
Yes you only need a few mm to mount the motor. ..Clivehttp://www.mycncuk.com/attachment.ph...id=15665&stc=1Quote:
Originally Posted by Noplace
As Clive says you only need 2 or 3 mm, I've got about 3mm left for my Z stepper out of the 20mm plate...there's no real force acting on it so it doesn't need to be super strong.
Thanks I think I got it now, here's one of em with 5mm thickness for motor:
http://www.mycncuk.com/attachment.ph...id=15666&stc=1http://www.mycncuk.com/attachment.ph...id=15667&stc=1
Spot on....
I have never found a pulley separation calculator that got it right. I draw the two PCD's at around the separation I want, add two tangents to connect them as the belt would, trim the circles to those tangents, list the two arcs and one tangent then tally their lengths. Undo until I am back at two circles, tweak the separation and start again until I get it near as makes no difference. If you mount motor and shaft bearing in the same piece of metal you don't actually need any adjustment if your machine is accurate.
Make sure none of the pulley bolts coincide with the belt and if you are really canny you add a fixing for the plastic conduit that protects the motor leads, because that is never in quite the right place if you forget it now :eagerness:
Hey guys, so just encountered an issue which is upsetting but hopefully with your guidance I can fix it. I didn't get a chance to take photos of the machine to show the problem but I'll explain it first now and hopefully post photos later if needed.
so I connected the actual side plates to the X Axis rail and ballscrews:
http://www.mycncuk.com/attachment.ph...id=15668&stc=1
if you notice bottom 4 M5 screw holes are for connecting to the ballscrew nut bracket, this is the same screw you saw in the video, what happens is there is a mismatch between distance of the (4 M5 and 4 upper M8 holes) in the plate and the screw and rail distance so I have to lift the side plate a bit up to match the 4 M8 threaded holes and the when I screw everything fit the ballscrew is forced to strain upwards and causing me jittery movement if going slow along with noise and stalling at the far end side ( tested with drill just like video ) . it is opposite of result in video , very bad hopefully ill capture it but I don't want to repeat putting the sides haha.
so my question, can you just solve this by machining the side plate to have the same slot solution as we discussed for motor plate?
instead of 4 m5 holes ill have a slot of same radius but gives me little tolerance to adjust the height correctly?
hope this is clear, if not I will post a photo of the real thing but the place I have my stuff in has no Air conditioner so I have to plan a shower after it haha.
You can slot holes so that you can have adjustment there's no problem there, of course it's better if they're spot on but once they're tightened up it won't really matter. I cocked up the dimensions on my Z back plate for the lower bearing plate for the Y axis and they're slightly slotted, it's still fine!!
After you have put in the slots and you get it all true you could then drill another hole through and put some dowels in to hold it in position. ..Clive
one of the local workshops made it for me, will test and cross fingers and hopefully no more stress on ballscrews.
on a separate note, back to the spindle I have tested it and seems to be working well with the relays and mach3, the speed is not being controlled accurately and I suspect the spindle pulley setting in mach3 but still didn't figure it out, ill post a video of this issue soon.
but main thing about spindle is I ordered and received a braking resistor, its 200W 70Ohm as per the spec in the document. I know it's not needed but thought what the hell, I just have to revert the P14 setting the sylveski mentioned earlier and I think all the other default settings are good. if anyone wants to advice on this part please let me know.
thanks!
Quote:
Originally Posted by Robin Hewitt
This one has it right. Proven a couple of times. Also drawing circles with pulley external dimension / teeth/ as per specs, connecting circles with straight lines at tangential points, deleting unnecessary and using CAD to calculate total length has proven spot on, even for a couple of pulleys where small to none adjustment was necessary.
Sweeeet find Boyan, I couldn't get my head around it all when trying to work this out, this point and click link is great!
.Me
That calculator matches the sheet called "Belt Length" in mine:
http://www.mycncuk.com/threads/5848-...g-belt-lengths
Looks like there's a slightly discrepancy on the sheet where I did it the other way round. Perhaps I should have worked out the formulas myself, not copied the nearest source...It's two circles and two lines, how hard can it be!
I think the problem here is more the tolerances on the pulleys and belts - they're not much, but enough to require a small amount of center distance adjustment to get the correct tension.
Just had a go...
http://www.mycncuk.com/attachment.ph...id=15682&stc=1
Anyone want to check it?
Exactly. There is some small adjustment necessary as pulleys go bigger. So you should include the correct pulley formula in that calculations to begin with.
Here bellow is a screen snip from the parametric pulley i draw. The formulas are correct for any tooth count HTD 5 pulley
http://www.mycncuk.com/attachment.ph...id=15683&stc=1
Just checked, the mess I just posted correctly calculates the total perimiter for what I drew.
Silvaski - your formula there is helpful for drawing the pulley, as it includes the correction (0.57mm) for finding the difference between the pitch diameter and the actual pulley diameter. However for calculating the center distance and belt length, we only need the pitch diameter (D=N*p/pi).
Looking at the javascrip on the website you're using (http://www.product-config.net/catalo...r_functions.js), we can see the following:
Their expression for theta is the same as my alpha.Code:theta = Math.asin((pitchDiameterA - pitchDiameterB) / (2 * englishDesiredCD)); costheta = Math.cos(Math.asin((pitchDiameterA - pitchDiameterB) / (2 * englishDesiredCD)));
desiredBeltLength = 2 * englishDesiredCD * costheta +
Math.PI * (pitchDiameterA + pitchDiameterB) / 2 +
theta * (pitchDiameterA - pitchDiameterB);
For the overall belt length, the 2*CD*costheta is the same as my formula for 2*L, they just used trig not Pythagoras.
The expression pi*(D+d)/2 matches my formula - they've just factorized it and used diameters not radii.
The last item, theta*(D-d), is the extra length to account for the small angle of belt that is used due to the difference in pulley diameters. Again, if you re-arrange my formula then this term falls out. You can see if pulleys are the same size, i.e. d=D, then that part of the equation is zero.
So their formula is identical to what I just derived.
Then they round to the nearest integer teeth belt size and use some crazy looking formula to back-calculate the center distance.
Whatever floats their boat...Code:v = 4 * beltLength - 6.28 * (pitchDiameterA + pitchDiameterB); centerDistance = (v + Math.sqrt(v * v - 32 * (pitchDiameterA - pitchDiameterB) * (pitchDiameterA - pitchDiameterB))) / 16;
What's up gang , I'm in London on holiday and just ordered a nice vice from rdgtools and some clamps for this upcoming machine , at least make use of the free shipping haha.
Anyone got suggestions on useful things to get from the country but not so heavy?
A DTI to square up the vertical face of the vice jaw to the spindle (swinging finger type rather then vertical plunge type), plus some parallels to raise work up in the vice but keep it parallel to the base of the vice.
And sorry about the rain over here, it's supposed to be summertime.
.Quote:
Originally Posted by routercnc
Thanks for that routercnc, as a lay man I've often wondered about the purpose of these "parallels" that folk keep on mentioning, but hadn't yet got around to finding out. Now their purpose makes total sense, and here's a video.
.
Machining Tips: What Are Parallels Used For? https://www.youtube.com/watch?v=nlLVEXXlFnY
.
Cheers, Andy
Thanks I already got those covered before. no worries about the rain so far it hasn't bothered us and the weather overall is a step up from the humidity and heat lol. although it's quite fascinating how it alternates between cold and hot during the day and even both at the same time!Quote:
Originally Posted by routercnc
do you feel its like that or are we imaging it cause we are new to the place?
I have book marked it and I will give it a try next time I set a pair of pulleys.Quote:
Originally Posted by Boyan Silyavski
It took me a while before I could bring myself to mount pulleys with absolutely no possibility of adjustment, but now I can't imagine why :lemo:
Quick question gentlemen, on my long axis I have a motor ballscrew setup for each side, what is the best way to align & make parallel both rail blocks/side plates/etc before attaching the gantry pieces and make one of the motors a slave? should I get a long machinist square? I don't have one that would reach all the way to the other side atm but would that suffice anyway?
thanks!
I bought a straight edge and set one rail straight. Then put the carriage block on the beatings and set it square with a dti mounted on the straight rail. Then set the carriage plate square on the other rails carriages. Then put my gantry bottom plate on setting it square with both carriage plates by putting the end plates on as they fastened to both the carriage plate and gantry bottom plate ends, checked with engineers squares. Then drilled and loosely fastened the other rail at one end and sliding the gantry down the rail I marked, drilled and tapped as I went down so using the gantry to align the rails....
Another question gentlmen, when I mount my motors, how do I determine the best tension on the belts? both my gantry and Z will be belt driven and I have already used a calculator site to determine the belt length ( and bought it ) based on the distance between the points. but then what actual distance would I screw the motor at?
thanks!
Update:
had issue with my Z motor turned out the cable had some issue so I just cut one side and directly connected it to the driver instead of the 4-pin plugs setup, works fine now.
assembled everything and tested and so far satisfied, still I got a long way to get it right:
things need to be done:
-Spindle speed control via mach3 : had issue before of speed being off, probably needed adjustment of the voltage or something.
-limit switches : using software limit only at the moment
-checking alignment/parallel via DTI : to be honest I have no training on using this properly and feel like my machine doesn't have room to adjust correctly, however I can live with a little bit of error for now, as long as the thing works!
-making triangular support legs with leveling: something I missed was to make the frame have adjustable height on each corner, now am thinking of just mounting extra 4 pieces on each corner of the frame and have those lift the whole thing up and balance accordingly
-Drag chain attached to frame : again my stupid and impulsive attitude prevented me from designing a side where drag chain can sit so I have to think about manually drilling and just attaching a flat panel so it can sit on it, no big deal I guess for now.
-Double check tension of belts : again no formal training so no idea how to do it properly but by feel I think I got it decent tension :hysterical:
-Connect water cooling to spindle
-Cable management of Z axis
-Actually cut something : will probably try wood(MDF) first, then maybe try my luck with other material and ultimately aluminium, anyone wanna recommend speeds and feeds for me?
-and many more I'm sure, hope I get some positive feedback from you guys in order to make it better!
A quick photo of the machine:
http://www.mycncuk.com/attachment.ph...id=15949&stc=1
Video of axis movement , before mounting spindle( at time of this post it is still uploading but give me 20mins or so plz hehe)
https://www.youtube.com/watch?v=sIeMDkg2KVI
am sure u guys might have some comments, particularly on sound of long axis movement, had lots of issues with it being flexing/bending if I tighten the gantry too much or so, the ballscrew ends might need shimming but not sure how to approach it yet.
Your gantry motor belt is looking extremely loose on video.
Just google or youtube - timing belt tension - and you will be expert belt tension operator.
thank you already fixed it but I will have to learn the right procedure as you mentioned.
I tighten belts by making sure I can just about twist (by hand) the bit of belt run furthest from any pulley by about 90 degrees. I know this is also subjective but it should get you somewhere close
Hey again, yesterday I was finally able to test cutting aluminum after getting the t-slot table and fixing it in the frame. I need as much guidance and advise as you could provide me since I had several issues.
I was spraying the bit with WD40 as well as having the mist coolant system spraying water and air ( but the water/oil valve was off so only air ) and I did that to get the chips to clear since I was milling a hole, however it was far from ideal and although had chips flying in direction of air still had plenty not moving out of the hole, I did a slight adjustment to direction and angle of nozzle and helped a bit but I didn't want to just keep doing that.
second issue was that the chips that flu were flying onto my long axis rail and a bit on the ballscrew which was behind it, wasnt an issue now but it will definetly be one, I held on purchasing dust covers because the supplier i found asked for a high price, appreciate if anyone can point me to low cost solution on this part
third issue is that the piece was a bit hot to touch, so I guess I failed of having the heat transferred to chips instead of the part/stock, appreciate if anyone can guide me on proper oil/water/air combo for lubricating and cooling during milling aluminium.
spindle was around 7500RPM feed rate 150mm/sec (taking it real slow to be cautious) however I read somewhere that aluminium needs a bit higher feed rate so to not stick, but not sure about that, your help here is again appreciated.
cutting tool was 4flute 8mm HSS, test was milling a circle with 23mm radius and 20mm depth, my stock was just a scrap and it needed facing on all sides like no body's business, but this was just a test and wasn't worried about it being a bit tilted and not reach all the way through ( you can figure by the photo and the small cylinder piece left at the center)
I still am not sure how parallel my spindle is to my table and how much error is there when I move it length/side wise but it seems decent enough for now as I'm way below the level of making precise parts. will definitely be asking for tips on this as well but I also know that due to quality of parts and my labor it wont go beyond a certain level of accuracy and precision.
here are some photos, am sure you will laugh when looking at the back side photo but I will try to make it tidier hehe, also am a bit sad about having to put the vise horizontally as opposed to the standard way but thats because I opted for bigger/lengthier t-slot table for mounting large wood stock as opposed to having a a smaller t-slot table but horizontal slots instead of vertical. it is bothering to turn the vise but it's a small issue no big deal.
Attachment 16269Attachment 16270Attachment 16271Attachment 16272
It looks like you have done a profile cut to make the hole A pocket would have been better to have the hole cleared.
You don't say how many flutes the cutter has etc.
Sorry updated the original post, it was a 4 flute cutter. I just used an online g-code generator to generate cutting a hole, it goes down 3mm depth at a time and makes it a circle path. I'm already using hsmexpress so I'll do the toolpath on that next time and see.Quote:
Originally Posted by Clive S
Try a two flute cutter at about 14K with a pocket tool pathQuote:
Originally Posted by Noplace
Hi Khalid,
Nice to see it working. 4 flute cutters are no good for aluminium because has you found out you can't remove chips fast enough so they get re-cut chips causeing cutter heating of material and tool. Your very lucky you didn't go into melt down and Gum up the cutter with those feeds/speeds.
My standard setup is to use 3 flute Carbide Ripping cutters for roughing leaving 0.35mm wall material cutting approx 40-50% Dia DOC and feed rate between 900 -1600mm/min. Spindle speed 14000-24000rpm all depending on material grade and how big a hurry I'm in.
I Finish with a Full depth pass using single flute HSS to remove the 0.35mm material. Any where between 9000-12000rpm and feedrate 600-900mm/min.
When cutting Aluminium there is NO one cutter or feedrate/DOC etc suits all and each grade of material cuts different, infact the same grade can differ from batch to batch. Lower grades also have hard and soft spots which can catch you out if cutting parameters are close to max'd out.
So for this reason you'll find your constantly tweaking with settings to suit your machine and material being used at the time.
In all cases you need at least blown air cooling to clear chips and ideally you want some form of coolant, mist, odourless mist or flood all work good.
Another tip is don't use cutters any wider than 8mm if slot cutting at any depth has the cutting forces increase hugely and stress the spindle/machine. Wide cutters are good for shallow surfacing or deep edge milling with lower step over. Just avoid deep slot milling with them.
new issue with auto tool height, any insight is highly appreciated
I’m using C35 http://cnc4pc.com/Tech_Docs/C35R1_2_user_manual.pdf to control my machine and everything works great, trying to setup auto tool height but there is a problem with the wiring. I tried wiring port 15 and ground pin as the two points for my tool height accessory and there is nothing wrong with it until I hook the thing to the tool/spindle. the issue is that my spindle is grounded to the backpanel of all electronics and that in turn goes back to the earth wire in the electrical socket. never had an issue until the auto tool height wires touch each other while also hooked to the endmill/spindle, when they touch suddenly the unit gives an error and stops working until I re connect to the PC and restart mach3.
so in short, if the C35 port 15, ground port and my ground point all connect Mach3 will pop an error that the motion controller is disconnected.
I also saw very tiny sparks when I made the plate touch the spindle and the wire with hook.
have I made a grave error by putting my VFD in the electronics enclosure which in turn made the spindle ground connect to it and in turn made my whole machine the ground point?
I guess no one cared about the previous issue since it sounds idiotic from my side :cower: haha anyway I solved the issues I verified my grounding concept is sound ( I think lol )
appreciate any input on a new issue: I got my X and Y axis setup to travel at 10m/min 1m/s^2 and they do so decently but my Z can't handle more than 7m/min .5m/s^2 , I tested the motor without any load and it was fine upto the desired speeds but not when connected back again with the belt. my question is what can I do to make it better? two reasons I can think of is the linear rails might not be aligned perfectly with the ballscrew causing it to use more force, should I open it all up and tweak? also the weight of the spindle is maybe 12KG or so (feels heavier for sure) might it be that the motor just doesn't have enough torque to move it at high acceleration?
all my motors are 3.1Nm nema23 from zappautomation btw
Do you have 1610 ballscrews on X and Y and 1605 on Z as per a normal setup? Because that will affect your speed on Z.
Sent from my XT1072 using Tapatalk
Yes I do indeed, just to clear confusion in case there is any, the steps per and speed of the motor in mach3 is all setup correctly and I was able to reach the speeds by increasing my motion controller frequency which gives me the option to. so there is no software/hardware limit that prevents me from entering a larger speed and acceleration if I wish, the problem occurs by having the motor stall after a little jogging.Quote:
Originally Posted by CharlieRam
but if you mean that there is an inherited limit in using a 5mm pitch screw that I can't go past for example 7m/min can you please let me know if such is the case?
Yes. You would have to spin the ballscrew twice as fast as a 1610 to achieve the same linear speed
Sent from my XT1072 using Tapatalk
I'm questioning why you want all that speed on your Z? I've got my Z at 7m/min and its plenty fast enough. What are you doing that needs more speed?
Ps I've got a 1605 ballscrew on mine.
no I don't need that speed at all, sorry I'm talking about the acceleration here mostly, I was just wondering how to achieve higher acceleration without stalling.