All the best with your build
I already gave you a link., having a hard time finding small oz-in 34s
The motor I linked to above should be faster than any similar sized Nema 23, provided that you run it at about 60V, with a quality drive.So am i wrong in the logic or a high force 23 would be slower than a small power 34 ?
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
All the best with your build
That dual beam gantry is not going to be very rigid. Try to make the extrusions bigger, and put a thick solid plate on the back of them, maybe 10mm thick?
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
You are really damn right , you even sent me a link but i didnt knew your experience yet and i am reading so many things my brains are a bit oversaturated and we're on the page 2 now ... (i am actually in accident recovery post TBI and it brought up ADD ... im sorry i feel a bit like a 35 years old teenager )
I will follow your stepper link to order them and i have a small last question before submit my order . i am wondering what is the weight moving good range for a 465oz-in stepper . i am using the mass calculations of my Fusion 360 (yes did set the materials properties of the aluminum parts and the steel ones to have the good calculations) and it is already at 23 KG but no gantry sides plates , Z-axis (rails and assembly) , steppers X-Z and the ATC spindle (the one i am looking at is 19KG) in the design yet but i would probably end up around 50KG (100lbs) and two Y-axis steppers/ballscrew to move it . Probably more weight than the screenshot of the El Beast build i showed in a previous post who is smaller than mine .
I am also still wondering if a 2.5kW ATCJGL-100/2.5R24spindle kit Jian-Ken (1900usd with water pump , VFD and shipment fees) would be very okay for my wood and Aluminum needs or a 4.2kWJGL-110/4.2R24kit from Jian-Ken (2115$ shipped, would be almost double power for only 10% price increase ) if it would be usefull or never need it at all ? I remember Wizard said a bigger spindle will drain more power amps from the electrical box but when not using 100% of the power available it would drain more ?
i was also wondering if specs from the steppers called " HOLDING TORQUE " is their actual movement force or it is exactly what amount of torque they can sustain without skipping a step or moving out of position , like their "car handbrake" , not the real engine HP or something. I just fell on these info/explanations and the actual movement power is really related to the Amps rate like you told earlier .
from a website i opened in my Google search , looks good infos !
https://www.motioncontroltips.com/fa...olding-torque/
Holding torque
A stepper motor’s holding torque is the amount of torque needed in order to move the motor one full step when the windings are energized but the rotor is stationary. Holding torque is one of the primary benefits that stepper motors offer versus servo motors, making stepper designs a good choice for cases where a load needs to be held in place.
Stepper motors can hold a load against an external force when the motor is stationary.
Image credit: Oriental Motor U.S.A. Corp
Holding torque is typically higher than running torque, and is limited primarily by the maximum current the motor can withstand. From a practical standpoint, holding torque is the sum of the magnetic force exerted by the coils to hold the motor’s current position, plus the detent torque. Once the motor is moving, the torque available at low speeds equals the holding torque minus two times the detent torque (because the motor has to work against the detent torque).
well , the backplate i just made a quick 2mm extruding of my first sketch and not decided the thickness yet . I really like the pattern of polygons , very pleasing my eyes for the moment ! I really like the twin beam that will house the motion components in between them . I could maybe use lower 80x80 beam and 40x80 on top to keep a solid squared gantry but my extrusion supplier really knows the behavior of the available profiles , got 4-5 different types of every dimensions . He was suggesting me a single 8080 beam.
Those motors are the best choice for 5mm pitch ballscrews. 100lbs is not a problem
Holding torque is the torque when the motors are NOT spinning. The faster they spin, the less torque they have.
If you don't know, then you probably don't need the bigger one.I am also still wondering if a 2.5kW ATCJGL-100/2.5R24spindle kit Jian-Ken (1900usd with water pump , VFD and shipment fees) would be very okay for my wood and Aluminum needs or a 4.2kWJGL-110/4.2R24kit from Jian-Ken (2115$ shipped, would be almost double power for only 10% price increase ) if it would be usefull or never need it at all ?
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Allright , very nice , ordering the 465s 6A today !
Allright ,so wont go too forward in the spindle kWatts and this review is really showing good points compared to the cheap chinese ones , especially the noise!! and probably a chinese cheapo telling 2.2kW is not giving it for real ...
Now still wondering which type of gantry i would need ... high rails and short gantry plates or rails lower or even flat height with the surface .... , my aim is aluminum machining soooo , pros and cons of the different rails heights ? I also added a Z-axis CAD i found on GrabCad this is usefull!!
You really need one BIG gantry beam. The bigger the better. Steel would be even better.my aim is aluminum machining soooo
What you have will flex easily with very light finger pressure at the collet.
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Too some extent what you need depends upon what you mean by “aluminum machining” but I gave to ageee with ger21 the bee depicted here is flimsy. Beyond the mechanical issues you should also consider other needs Aluminum has. You will need good spindlecontrol and a form of coolant supply. Coolant and even aluminum swarf is messy town enclosed machine is nice.
I strongly suggest reading the stickies as one of the threads there goes into beam design in depth. It might be over simplifying things but bigger in cross section is better. Of course detail is manner and the beam needs to be properly supported. The goal is to minimize deflection and twist which can be very high in long thin beams. Allied with this is having enough width to allow suitable separation of the ganytry saddle(Y axis saddle) so that they can handle the twisting forces from the Z axis. Again the wider the spread the better but you can’t be increasing beam size forever so you need to find the happy point.
For easy access, especially on larger machines with heavy parts, you will want a flush table top. This is a human factors thing to make loading the table easier. Even if you have mechanical help, with a job crane for example, you still want to avoid pinch points. In my opinion you have massively more options on a small machine handling light parts and I don’t see one design being spectacularly better than the other., pros and cons of the different rails heights ?
This actually brings up a point, human factors are important in machine design and implementation. Any design that compromises the person working on the machine should be excluded. Even placing a ten pound object can be a problem if that puts a person in an unnatural position.
I don’t like anything at all about that gantry beam design.I also added a Z-axis CAD i found on GrabCad this is usefull!!
You are free to do what you want but you also may want to consider the issues others have with light weight machines trying to machine aluminum. At a minimal you will want a machine that is 10 times stiffer than a machine that can do quality work in wood. There is even a recent example of somebody trying to use a flimsy wood router in aluminum.
Depending on the alloy, the temper, phases of the moon and other unknowns, aluminum can actually be tricky to machine. Chip welding is a real problem that will break cutters real fast on a CNC machine. A good surface finish demands a stiff machine. In a nut shells well built machine frees you from another parameter that may be causing you trouble in Aluminum.
In any event there is a common problem in DIY machines and that is a weak gantry beam assembly. The larger the span the greater this issue. There are lots of reasons for why this happens, budget is often the biggest factor. However not understanding the mechanical issues is also a big one. I tend to push towards a robust gantry especially if the builder has high expectations. Building a machine that is expected to process aluminum as it’s only work load puts you into the high expectation category.
Yeah I know we can easily break a budget here. However a machine that doesn’t work as intended really blows the budget. In any event high expectations usually translates into high prices.
That gantry beam is about as rigid as a soggy lettuce leaf.There is absolutely nothing to stop the weight of that humungous Z axis and huge spindle just pulling it several degrees out of line.We haven't even mentioned what the cutting forces are likely to do.A big steel box section with ends that are triangulated to well spaced sliders would have more of a chance and steel isn't that expensive compared to that brute of a spindle.
I'm not so sure I agree with this as an absolute. You can drive a 1605 with nema 23 440oz/in direct drive and get 2000 mm/m if you don't belt/gear reduce and rather direct drive them. This speed is going to put a heck of a load on your cutter and machine. The grain of sale i'd give the advice from ger21 here is that the motors and drivers may not be the weakest link in your machine. in my case i'm using DRV8825 drivers ( these are better suited for 3d printers) putting out about 2A (with cooling) and there is more than enough power to highlight the rigidity issues of my machine. I have drivers that will output more power but I can't really utilize them since my machine is running plenty fast for my skill level and making super fast rapids introduces many risks to your tools! I make enough mistakes that slower rapids are better for me. I broke a cutter the other day just taking a part out of the workholding!
That said ger21 knows his stuff and I'm sure if you followed all of his advice you'd have a very capable machine!
I am amazed at how well my machine works based on the many flaws it does have. It is better to have something that works and you can get some experiences with than seeking the perfect machine/design.
my final .02 is that the frame is maybe the hardest part when building for a large cutting area. Flat is hard, square is hard, parallel is hard and it only gets harder as you make your parts bigger!
Thanks guys for the opinions , it is my first build design . I thought my beam would not be super stiff but i do no have experience on builds like this , maybe would have been stiff enough so i wouldnt overkill it for nothing and costing more . I really appreciate your thoughts , it helps me following a direction!! I havent found many aluminum router builds on the web but the ones i found were pretty insanely nice and looked a bit overkill . Some i seen were wood working routers doing some aluminum milling tests but nobody shows up the differences of the surfaces finish in between the machines so it was hard to really know the direction of my build !
So i will check out for my gantry beam design and make it stiffer .The gantry offsetting the beam to center the center mass over the linear bearings would work but not cancel the twisting in between the spindle and beam itself, i didnt thought about this yet .
The beam lenght would be just 20" longer than the Y-axis , i am not really scared by this but will hunt for better stiffness , steel tube wouldnt be easily twistable so i will orient there. My doubt with steel was to have trouble welding anything and keep everything square and flat without bringing this to machine shops to shave/leveling straight
What i am imaging in my head right now is that i could use 2 steel tubes like 1/8" thick , probably 1.5"x6" and lay them on eachother and weld them together and it would bring internal structure in all directions instead of an empty bigger tube who would also be more heavy. I have almost 20 square tubes 8 feet long of 2"x2" steel but they are about 80 pounds each and they feel flex a bit when the two ends supported and stepping in the center .
Or maybe could use a heavy aluminum H beam and bolt it down on thick gantry plates with gussets 45deg to stabilise . Not sure of the price of this kind of beam but the ones ive seen in a distributor wharehouse looked pretty flat and straight.
Thanks alot guys for your knowledge support , i am appreciating a lot !!!
And ...........
HAPPY NEW YEEAARRR!!!
I am pretty excited on this build and i am trying to find a last specific dimension range i should have between the gantry base bearings. For aluminum machining , what would be the good way ? now at 250mm(10 inches) used on the rails so shortening the travel . Am i overkill on the width , correct or not enough ? I can see differences on any projects so my research is not based on standards so i am curious.
Right now lots of parts are on their way and received quote for the steel tubes and an Aluminum surface plate. Now i would like to be sure i would be good with the gantry side plates dimensions to send the correct DXF to have them cut
**Parts coming**
- steppers
- drivers
- spindle ATC
- tool holders +collets
- Hoses, Drag chain, pneumatic solenoid , pulleys, belts , small things
Letomoto
A few can moments to your recent posts.
When you or anybody else says they want to machine aluminum , There is A very broad range of “what that means” possibilities. The problem that many see here is that that gantry wouldn’t do for wood working in many cases. People have focused on this and comment as such because they want to see you be successful from their perspective. Each person has an idea in their mind what would be right but here everyone is in agreement that the current design is not acceptable.
As for designing in a channel for motion hardware, that isn’t a bad idea if needed. Do realize though that the linear rails and bearings already create a fairly substantial dead space under the axis saddle. Often you are better off working within that space provided by the rails. In n any event this should all be resolved in up front design.
The desire not to want to go to the expense of welding and machining is understandable but you make an assumption here that Aluminum extrusions are perfect. They aren’t, though often good enough for wood working. Generally machining aluminum implies a higher degree of accuracy and straightness. This can mean that an aluminum structure requires machining too. If not machining other remediation methods may be required.
I find one aspect of the proposed design a bit puzzling.Those steppers on the side look huge and you are planning to connect them to the leadscrew by means of what appear to be quite light belts.Why not locate them in line with the leadscrew and use a direct coupling?You might have to move the leadscrew along the machine to allow them to align.What size did you finally select?
My final thought on the machine isn't meant to be as negative as it might appear,but did you investigate buying a second hand Bridgeport and converting it?You could then gain experience of the control software,the machining processes and produce the parts for your router.The machine is intended for cutting metal and after a conversion you would be able to sell it and recoup some money.You might even find it is the only machine you actually need.
Well , yeah i understood extrusion was good for wood but not stiff enough for alum . i redid the whole frame with the rectangular steel tubes real dimensions available locally , using 3"x8" tubes for the beam and the tall sides . i asked quote for 3"x6" tubes and it would cost 160$ , also asked for the 3"x"8" tube and it god damn jumped to 433$.... will retouch the positioning of the sides , just sitting on the 3"x3" beams who connects them , will look a bit less cute but will save 273$ and would shorten the size of the gantry plates , this wouldnt be bad for the wallet .
And for the Axis bearings i am not very understanding your opinion , " linear rails and bearings already create a fairly substantial dead space under the axis saddle" is the saddle one gantry side plate or it is the distance in between the two plates ? And Up front design means what ? I am sorry not understanding everything , i am a frenchie
i am appreciating the opinions , i am learning quite a lot of things
For the steppers they are Nema34 and i found the 3D on Grabcad and took a belt drawing to just add them on the project design. The belts ordered are about 5/8" width , will be strong enough
The Direct coupling would be adding about 8 inches of lenght to the machine and i have to build it compact because of the small space i have in my workplace ...
Not sure about your suggestion moving the leadscrew along the machine , arent they already along the machine ? the ballscrews are SFU-1605
And converting a manual benchtop mill to cnc i did it last year , some pictures of the build ongoing but now is done and working but way very small surface can't work on anything bigger than 6 inches Y-axis and 16inches X-axis , this is why i am starting a 3'x5' router table
Having that mill will be a huge advantage when you need to make parts for your router.The experience of making it work as a CNC machine also gives you a big head start on configuring the software for the router.I suggested moving the leadscrew and stepper to eliminate the possible weak link of the toothed belt.If you need to reduce the footprint of the machine and use a belt it would probably be a good idea to make a cover of some kind to eliminate the risk of anything getting snagged by the belt or a fragment of the workpiece falling in there.A chunk of debris in the wrong place could be catastrophic.I know a man who wrecked a racing engine when a small clip got into the camshaft drive belt and that was a much bigger belt than the 5/8" quoted.
Yes a cnc mill like that is ideal for making parts for a router....wish i had one of those