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7 Attachment(s)
Yet another epoxy granite mill
Hi,
I've had a lot of inspiration from this forum, so i think it is my turn to give something back. I've had an idea of building a large VMC for many years(decades?) and now i've finally come to the point where i'm building one. So this thread will contain the buildlog for my project, hopefully it can inspire others to follow through on their ideas. It is important to note that there is no major endgoal for this project. I have no vision of me making a living or whatever of this machine somewhere in the future. This project is all about the process, the learning, the development and the challenges. If this project should have a tagline, it would be "It's not the destination, it's the journey".
I've previosly made a gantry-styled router for full sheets:
Attachment 459702
... and here i've had my first experience with gcode, servo motors, endmills etc... It uses 2005 ballscrews, 25mm rails, clearpath servos and a Centroid Acorn as controller. I learned a huge amount on this project, among other things the importance of rigidity and mass distribution... I also had the plan to use this machine to help me making of the the next machine...
So i've spent a lot of hours drawing and deciding on a "knee type" or a "gantry type" mill. And i ended up with the knee-type working best for me. The rough design looks something like this:
Attachment 459704
Key information about it something along these lines:
- Height 196cm (my garage port is 200cm high)
- Weight: ~2500kg (~1700kg epoxygranite, rest is mostly steel)
- Controller: LinuxCNC
- Axis servos: CTB - 2,2kW on all axis
- Spindle servo: CTB - 7,5kW
- Spindle: Fuka FKS1201 with ATC and through-spindle coolant
- Rails: 35mm Hiwin RG rails
- Ballscrews: Hiwin 3010 ground C3
The decision making process for arriving on the above components are not based on clever math or elaborate spreadsheets. Rather i've been looking at how Haas or other professionals have done things and how other DIY projects have turned out. I started with the spindle and worked my way "backwards" through the mill. I did some calculations on the ballscrews, bearings etc, but nothing fancy. Then i've tried to make the best compromises for the project with a balance of "endresults" vs. price vs. time..
I've received the spindle and tested out the toolchanger and making sure i understood how the ATC and CTS works. Here is a picture of the spindle itself and my testsetup:
Attachment 459710Attachment 459706
I'm yet to have to servos running, because i'd like to make use of EtherCAT, but i'm having a hard time getting it working in LinuxCNC, i'll get there, for sure, but it is a steep learning curve:
Attachment 459708
I'm almost done with the molds for the EG. I'm using phenolic plywood("formply"):
Attachment 459712Attachment 459714
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4 Attachment(s)
Re: Yet another epoxy granite mill
I've also started on the steel inserts:
Attachment 459718Attachment 459720
And i just got the 200L epoxy(ResinL + GL2 from R&G) and the 2000kg "sand"(Silimix 282):
Attachment 459722Attachment 459724
Hopefully i will get the inserts and forms completed within the next couple of weeks and get ready for casting at the end of march...
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Re: Yet another epoxy granite mill
Very nice mate, you got a lot of work ahead of you, looking forward to seeing the end result.
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Re: Yet another epoxy granite mill
Watching with interest. Looks like a great build.
Axis travels?
That frame design is usually called a "C frame"
Knee usually refers to part of a Bridgeport mill design.
How much $$ was the spindle?
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
Momentz
Very nice mate, you got a lot of work ahead of you, looking forward to seeing the end result.
Thanks! I hope there is a lot of work in the project;-)
Quote:
Originally Posted by
pippin88
Axis travels?
That frame design is usually called a "C frame"
Knee usually refers to part of a Bridgeport mill design.
How much $$ was the spindle?
Ah! Yeah, i learn something new every day on this project :-)
Travel is going to be X: 650mm, Y: 450mm, Z: 580mm (max spindlenose to table: 680mm).....or thereabouts :-)
The spindle itself was 1600USD, pneumatic cylinder was 130USD, CTS rotary union(LX86V-244) was 440USD and shipping was 650usd. I talked to a Tracy Ding at https://ntphoenixtree.en.alibaba.com/ and she has been very helpful and professional through the process... I've been doing some minor checks on the spindle itself(runout etc) and verything seems well within spec, actually quite a lot better than spec as far as i can tell... i have yet to make chips with the spindle, but besides that i would recommend them...
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Re: Yet another epoxy granite mill
Looking really good !
Do you plan to have double piece base ? there is visible separation line in base that is why i ask
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Re: Yet another epoxy granite mill
Hello,
This is a weird but serious question: Would you be interested in making a smaller size casting for me? I would pay you of course and handle shipping to Portugal.
I have never done anything like that ; i am not a machinist (yet).
Why am I looking to have something custom made?
Because the floor of the only space I have available is not strong enough to handle heavy machinery and I am not allowed to make any changes to it.
So... the only solution is to make somethin small and light(ish)...
Thank you,
Jorge
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Re: Yet another epoxy granite mill
Hello, Jorge
I have a couple of Epoxy Granite Machine Bases that were made by Intelitek for their Benchman and Prolight machines. The machines were designed for small prototype parts and for education in trade schools. The base weighs around 110KG without any components mounted. I have 2 assembled machines with the same base and the axis travels are X=305mm, Y=152mm, Z= 228mm. I purchased the bases in order to make a micro high speed milling machine from micro components but I only need one for that project and have an extra base if your interested. It’s a 1 piece base with precision ground steel inserts for mounting your rails onto. Message me if you are interested.
Regards,
Jose
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
rdc02271
Hello,
This is a weird but serious question: Would you be interested in making a smaller size casting for me? I would pay you of course and handle shipping to Portugal.
I have never done anything like that ; i am not a machinist (yet).
Why am I looking to have something custom made?
Because the floor of the only space I have available is not strong enough to handle heavy machinery and I am not allowed to make any changes to it.
So... the only solution is to make somethin small and light(ish)...
Thank you,
Jorge
Hi Jorge,
No, not right now, sorry. I would encourage you to try and make it. It is not that difficult...it just takes patience and great care...
/Thomas
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1 Attachment(s)
Re: Yet another epoxy granite mill
Progress has been slow the last couple of weeks. The kids, the wife and me took turns being sick(not Covid, just a cold, but still) the last couple of weeks...
Have been struggling a little with EMI on EtherCAT when i enabled all the drivers, so i took the decision to make the "high voltage" cabinet for the 3 axis and the spindle. I've just put it on the wall for testing purpose:
Attachment 461452
...it helped a lot on the noise...actually it eliminated it completely and i was able to power on all drives without the EtherCAT bus acting up... so it was defently a EMI issue i had earlier...
Next step is to get LinuxCNC to run all the drives as i'd like...and later this week i'm going to finish the last inserts for the EG casting...
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
lukahr
Do you plan to have double piece base ? there is visible separation line in base that is why i ask
Yes, the frame consists of a lower part and a top part. This is the only way i can get the steel inserts machined afterwards. The inserts will be milled and then ground. After that the two pieces will be assembled and aligned...and then glued into place using a special epoxy...
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Re: Yet another epoxy granite mill
I have the servo's running! LinuxCNC has a somewhat steep learning curve, to say it at the least! It took me a while to nail the whole EtherCAT thing i LinuxCNC, but now it works! It works! I'm high as a kite right now, this is AWESOME :-D
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Re: Yet another epoxy granite mill
Hi Thmas- Well done. Looking fwd to your journey... Which Silimix where you going to use? Peter
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
peteeng
Hi Thmas- Well done. Looking fwd to your journey... Which Silimix where you going to use? Peter
Silimix 282
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Re: Yet another epoxy granite mill
Notes for my own reference and if others choose CTB servo and drivers and find this via Google or whatever. I had some trouble getting EtherCAT to work in the first place. With these driver settings i was able to get it working...
1. Remember to order the drives with EtherCAT modules(i had to order these afterwards and install them myself, easy peasy, but they might aswell install it during assembly)
2. Here is a list of registers and what i've found to work(some of them might be default):
A1.00 = 1 (enable advanced features, nessesary to set the registers below)
A1.02 = 2
A2.00 = 2
Bn.06 = 0
Bn.13 = 1 (depending on your cycletime in the controller. I've setup 1ms in LinuxCNC)
Bn.21 = 0 (depending on controller, but the driver in LinuxCNC behaves like Beckhoff)
Hn.30 = 0
Hn.33 = 0
3. To clear any encoder alarms after connecting cables, set Pn.05=0
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2 Attachment(s)
Re: Yet another epoxy granite mill
And again for future reference, here is the manual + EtherCAT reference document.
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Re: Yet another epoxy granite mill
I also finished the design of the way covers and ordered them last week:
Attachment 461494
The next step is an enclosure for the entire thing...
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Re: Yet another epoxy granite mill
Where did you ordered waycovers ?
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
lukahr
Where did you ordered waycovers ?
With these guys:
https://www.alibaba.com/product-deta...834288030.html
...haven't gotten them yet, so can't vouch for quality etc.... it is always sort of a gamble with these suppliers, but we'll see when they arrive...
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Re: Yet another epoxy granite mill
Interesting, are those linear rail cooling bits on the z axis? I'm interested on what your idea is on how to make these. I have a slot in them and plan to partially squash a copper pipe on one end so its round on one side but flat on the other, like you'd do with heatpipes.
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
ardenum
Interesting, are those linear rail cooling bits on the z axis? I'm interested on what your idea is on how to make these. I have a slot in them and plan to partially squash a copper pipe on one end so its round on one side but flat on the other, like you'd do with heatpipes.
I think the ones you are refering to are the guides for the waycovers? I made the mistake and not taking waycovers into account when i ordered the linear rails, as they could have been used for the waycovers...so the ones i ordered was too short to be used as guides for the covers...instead, i solved it by mounting two pieces of 15x30mm smooth rectangular tubing along each axis instead...
Regarding the cooling... i'm still not sure if it is nessesary or not :-/ My plan was to add coppertubing to the casting, including one pipe going down on the backside of the steelinserts for the rails....and make the ballscrew nut such that i can pass water through it.... but i'm kinda abandoning all this because i don't believe it will have a real impact on my machine... but i might be wrong? What are your plans regarding this on your build? I know that "all the cool kids" do it(KERN and the like)....but is it a must on hobby machines like this one?
Have other NOT done it and regretted it later on? Or the opposite?
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Re: Yet another epoxy granite mill
Managed to do some testing on the ballscrews today. One of the things that had me worried was if i chosen the right preload for the ballscrew. As usual i have no idea what i'm doing, so i just took an educated guess;-) Sort of anyways....
Well, i hooked it up in a test-setup on a table:
Attachment 461558
Then i jogged it back and forth and the driver says ~20% load max of the rated torque...almost the same at slow speed and full tilt(30m/min)... which is somewhat higher than i expected(hoped?)...but... is it too high? What is normal here? I am told that the servo's can run up to 300% for a period(30min), but i guess that lower is always better...
I've also checked the linear rails(which are rollers, also with heavy preload), but even though they are a lot harder to move than the average "chinese knockoff", it requires no where near the torque as the ballscrew does as far as i can tell. So i'm not worries about excessive torque waste here(maybe 1-2% ekstra)...
My thought was that i could change the balls in the ballscrew to a smaller size...maybe.... i'll have to contact HiWIN and ask if that is the procedure(anyone?) and if i can purchase the smaller balls... but first i'll have to decide if i'm happy with the current dragtorque or if i need to do something to lower it...
Any inputs are greatly appreciated!
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Re: Yet another epoxy granite mill
Ah I was seeing two holes on the top of them so I thought they are cooling channels.
I'm building mine to last me a lifetime, but I'm casting in UHPC, I'm thinking that EG won't have an issue of 'cracking' if the steel guides expand slightly. But concrete is another beast so even slight expansion might put pressure on the inserts enough to develop some microcracking around them in the UHPC if the guides expand from heat. I'll be putting pipes in the casting like you described and on the under rail inserts.
Whether hobby machines need such cooling, the answer is probably not. I'm doing it for the peace of mind and because it's a cheap way of 'making sure'. A few copper pipes and a pump doesn't even come close in cost compared to the rest of the parts. So I don't see any reasons why not to do it. Here's a video, I think is a great and cheap method of cooling the rails. Starts at 1:08
https://youtu.be/y3lZ_AFvb7M?t=69
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
badhabit
Let us know when you get them, I will soon need waycovers for my build :D
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Re: Yet another epoxy granite mill
Are you going to be lubricating the things automatically or manually?
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
ardenum
Are you going to be lubricating the things automatically or manually?
The plan is to lubricate it using oil, automatically. I already have the pump, tubing, fittings and progressive valve distributors. But i've actually been wondering if it is better to use grease as lubricant?
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
badhabit
The plan is to lubricate it using oil, automatically. I already have the pump, tubing, fittings and progressive valve distributors. But i've actually been wondering if it is better to use grease as lubricant?
Nice, I'm also doing progressive lubrication. I'm also on the fence when it comes to oil/grease, mainly because I haven't decided on the pump yet. I guess your pump can work with both? Did you get those from china too? I found 2 companies on alibaba for the lubrication system:
Jiaxing Jianhe Machinery Co., Ltd. https://jianhelube.en.alibaba.com/?s...hop_plgr.88.28
Taizhou Yuhao Hydraulic Machinery Co., Ltd. https://cnyhyy.en.alibaba.com/?spm=a...385c672fcHpkDZ
If neither of these, I'll go with either Delimon or Graco.
As for the system I have 4x 6-valve dividers, one each for each axis and one main. I guess you didn't model them in then? It was a pain for me because I had to make fittings models from drawings, I tried getting SKF steps from partscommunity but they block accounts with normal emails(yahoo, google etc.).
Here's how my bed looks like underneath:
https://i.imgur.com/H7BtL6f.png
Remember the bottom 2 valves can't be blocked and have to connect somewhere.
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
ardenum
Nice, I'm also doing progressive lubrication. I'm also on the fence when it comes to oil/grease, mainly because I haven't decided on the pump yet. I guess your pump can work with both? Did you get those from china too? I found 2 companies on alibaba for the lubrication system:
Jiaxing Jianhe Machinery Co., Ltd.
https://jianhelube.en.alibaba.com/?s...hop_plgr.88.28
Taizhou Yuhao Hydraulic Machinery Co., Ltd.
https://cnyhyy.en.alibaba.com/?spm=a...385c672fcHpkDZ
If neither of these, I'll go with either Delimon or Graco.
As for the system I have 4x 6-valve dividers, one each for each axis and one main. I guess you didn't model them in then? It was a pain for me because I had to make fittings models from drawings, I tried getting SKF steps from partscommunity but they block accounts with normal emails(yahoo, google etc.).
Here's how my bed looks like underneath:
https://i.imgur.com/H7BtL6f.png
Remember the bottom 2 valves can't be blocked and have to connect somewhere.
All my libricationgear is leftover from another project, so i'm not even sure i'm going to use it. At the moment it is the plan to use it...buuuut, the stuff from the two manufacturers you've posted look kinda promising!
I haven't modeled it other than a couple of mounting holes... i'm not a huge fan of Fusion360 way of modelling pipes(i tried, failed and dropped it)... but it is for sure som impressive detailed CAD drawings you have! I'm slowly starting to feel the "CAD death", i just want to build something :-)
One thing, though: it looks like you are referencing the railtrucks on both rails...is this intended?
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
badhabit
All my libricationgear is leftover from another project, so i'm not even sure i'm going to use it. At the moment it is the plan to use it...buuuut, the stuff from the two manufacturers you've posted look kinda promising!
I haven't modeled it other than a couple of mounting holes... i'm not a huge fan of Fusion360 way of modelling pipes(i tried, failed and dropped it)... but it is for sure som impressive detailed CAD drawings you have! I'm slowly starting to feel the "CAD death", i just want to build something :-)
One thing, though: it looks like you are referencing the railtrucks on both rails...is this intended?
Thanks. Well you know, the more detailed I can make it, the less issues I'll have later on. That's how I'll have it machined, but I will only actually use one of the edges as reference, one side is 0.5mm longer while the other is 'cad exact' with the carriage. Sort of an insurance, in case the machined part is too short I plan to grind or scrape the other side myself.
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
ardenum
Thanks. Well you know, the more detailed I can make it, the less issues I'll have later on. That's how I'll have it machined, but I will only actually use one of the edges as reference, one side is 0.5mm longer while the other is 'cad exact' with the carriage. Sort of an insurance, in case the machined part is too short I plan to grind or scrape the other side myself.
Ah, ok, good to have some fallback strategies :-) My largest challenge is my own impatience, i really want to get going! But at the same time i know that it would be much better to complete the drawings in cad before I start doing anything... But i've spent hundreds of hours in CAD already and i really would like to get started making something :-)
Do you have a buildthread or anything similar where i can see your machine?
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
badhabit
Ah, ok, good to have some fallback strategies :-) My largest challenge is my own impatience, i really want to get going! But at the same time i know that it would be much better to complete the drawings in cad before I start doing anything... But i've spent hundreds of hours in CAD already and i really would like to get started making something :-)
Do you have a buildthread or anything similar where i can see your machine?
I know the feeling perfectly! There's no build thread yet, I had to relocate some of the machine funds towards living due to covid, so it's gonna take some time before I rebuild that $. I'm gonna start the build thread once I get my first shipment of parts(months away).
Anyway, here's un updated(and properly lubricated) bed, there were some issues before, I doubled the lubrication quantity going to the ballscrew nut and switched to flexible hoses and snap in fittings instead of compression ones. Hard piping looks great but I remember how many issues I had with hard tubes when I switched to water cooling my pc, there were leaks everywhere, not worth the hassle. The main hose is gonna go into an igus E3.15 e-chain(cable carrier).
https://i.imgur.com/xQEuUvK.png
https://www.youtube.com/watch?v=noLySw3Ghh0
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Re: Yet another epoxy granite mill
Counterweight is a pneumatic system right? How do you figure that one out?
Quote:
Originally Posted by
badhabit
Also, from left, that's a line filter? and a resistor for each drive? So instead of having a filter for each drive you do one big for the whole setup?
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
ardenum
Counterweight is a pneumatic system right? How do you figure that one out?
Yeah, i like pneumatics...so i guestimated how much my Z-sled weighs and then i took a pneumatic cylinder that could pull twice that at around 5bar. There is going to be a chain between the aircylinder at the back and the sled at the front. One end is attached directly to the Z-sled and the other end loops down around a sprocket on the cylinder and then back up. This gives me a 1:2 ratio and less movement in the aircylinder...
Quote:
Originally Posted by
ardenum
Also, from left, that's a line filter? and a resistor for each drive? So instead of having a filter for each drive you do one big for the whole setup?
Yeah, i had major EMI issues, so i added a 2-stage 30A line filter and some huge ferrit cores to the motor-cables. Mounted everything in the chassis and the noise problem (almost) disappeared. The manufacturer recommended one line filter for all drives...so just did that...
The resister is a break resister for each drive to make the stop faster...
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
badhabit
Yeah, i like pneumatics...so i guestimated how much my Z-sled weighs and then i took a pneumatic cylinder that could pull twice that at around 5bar. There is going to be a chain between the aircylinder at the back and the sled at the front. One end is attached directly to the Z-sled and the other end loops down around a sprocket on the cylinder and then back up. This gives me a 1:2 ratio and less movement in the aircylinder...
Just to be sure, you're using an air cylinder or a gas spring? Gas springs usually have a compressed gas eg. nitrogen inside them. I've read somewhere that counterbalance is done with gas springs? Sorry if this complicates things....
If its an air cylinder that means you have to pressurize the system prior to usage?
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
ardenum
Just to be sure, you're using an air cylinder or a gas spring? Gas springs usually have a compressed gas eg. nitrogen inside them. I've read somewhere that counterbalance is done with gas springs? Sorry if this complicates things....
If its an air cylinder that means you have to pressurize the system prior to usage?
It's an aircylinder, this one to be exact:
https://www.ebay.com/itm/SC-125x400-...0/161235846191
125mm bore and 400mm stroke. It will pull 688kg@6bar and my Z-axis weighs ~300kg. Since i have a 1:2 ratio in the chain between the Z-axis and the cylinder i'll effectively have a 800mm stroke and 344kg@6bar, so it fits perfect(Z-axis travel is just below 700mm)...
I'll add a buffer-tank and a pressure-regulator. This way i can dial in the pulling force and the tank will help minimize the pressure fluctuation as the piston moves up and down....
And yes, i need to pressurize the system before usage... but i'll need air anyways, e.g. for toolchange etc....
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
badhabit
It's an aircylinder, this one to be exact:
https://www.ebay.com/itm/SC-125x400-...0/161235846191
125mm bore and 400mm stroke. It will pull 688kg@6bar and my Z-axis weighs ~300kg. Since i have a 1:2 ratio in the chain between the Z-axis and the cylinder i'll effectively have a 800mm stroke and 344kg@6bar, so it fits perfect(Z-axis travel is just below 700mm)...
I'll add a buffer-tank and a pressure-regulator. This way i can dial in the pulling force and the tank will help minimize the pressure fluctuation as the piston moves up and down....
And yes, i need to pressurize the system before usage... but i'll need air anyways, e.g. for toolchange etc....
That's a hefty sized cylinder.
Thanks for the link, not often do I get parts handed to me on a plate and from a german seller....
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Re: Yet another epoxy granite mill
What kind of leveling feet will you use ?
Looking for them, for my machine :p
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Re: Yet another epoxy granite mill
Quote:
Originally Posted by
lukahr
What kind of leveling feet will you use ?
Looking for them, for my machine :p
These:
https://uk.misumi-ec.com/vona2/detai...ductCode=LM-16
Unless i find a better alternative(?)...i haven't bought them yet...
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Re: Yet another epoxy granite mill
These look nice but are even more expensive than what i found.
I’m looking at these in size 130mm cca 65€ per foot
https://www.elesa-ganter.com/en/www/...-elements--LWA
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Re: Yet another epoxy granite mill
I'm not sure how to even approach the feet. I thought I'll just use rubber pads and screw the whole thing to the floor anyway. I doubt it will vibrate at +5ton mass. But the rubber might turn to mush instead... I don't want to complicate it nor do I want to sacrifice any structural integrity for bolt cutouts.