[3d_cristian]

Hello all, for the last few years I have been designing a CNC machine that has the following features:
- spindle is powerful enough to be used for steel milling using typical end mills size and speeds/feeds as per tool manufacturer recommendation.
- easy to build with no special instruments, however it can produce components within 4 thou (0.1mm) tolerance.
- the machine size and the work envelope can be easily customized.
- low weight, on wheels, in order to be easily moved to a different location or inside a shop.
- the Z axis containing the processing head can be exchanged in order to use the machine for multiple manufacturing processes: milling, laser cutting, carving, etc, etc
- it can accommodate any motion card, CAM software or operating system (Linux or Windows)
- ATC with 5-10 tools
-vibrations produced during machining will not have an impact on the machine performance, maintenance or lifecycle.

Recently I have finish the prototype and posted the frame CAD files on Grabcad https://grabcad.com/library/powerful...teel-milling-1
During the prototype build iterations I have tested and recorded the vibrations levels for milling aluminium and steel. I will follow up with more vibration measurements shortly.

[awerby]

Have you actually built this thing and tested it on steel? If so, could you post some actual photos of it, and some videos of it cutting steel? If not, how did you manage to quantify its accuracy?

[3d_cristian]

Sorry for late response. I am working on video and vibration analysis in the same time. Formatting the results will take some time.

[3d_cristian]

With terrible sound and chatter or not, I still have build the "1st steel milling CNC made with T-Slot Extrusions"!

[mactec54]

With terrible sound and chatter or not, I still have build the "1st steel milling CNC made with T-Slot Extrusions"!

First No there are many that have been doing this with extrusion built machines with the same result, for a number of years this has been a hobby builder's dream to use there wood routers to cut steel, that is why we know what the outcome is, some have worked quite well check YouTube

[mactec54]

With terrible sound and chatter or not, I still have build the "1st steel milling CNC made with T-Slot Extrusions"!

Here is a Video of an Extrusion built machine cutting steel, the one main difference to you is the expensive spindle,( around $4000 ) being used is designed to cut steel and use's 30 Taper tooling even though it still has problems with chatter because of the machine construction it does quite well

https://www.youtube.com/watch?v=rTFn84UwFCM&t=585s

[joeavaerage]

Hi,
seeing is believing. From personal experience cutting steel or stainless is a WHOLE different experience than copper/brass/aluminum
and I've yet to see a 'router' style CNC machine do a credible job.

Craig

[3d_cristian]

Hi Andrew and joeaverage,
I have started to add videos to my youtube channel. The video and audio quality will get better on the next posts.
There are few comments that I would like to add:
- There is a distinct difference in sound between steel milling (at 3000 or 4000 RPM) and wood or granite carving (24000RPM). The spindle used for steel milling has an instantaneous peak torque of 30Nm (over 22FtLb).
- You can see from the are videos that are done on the same machine which I have built few years ago. Based on my design I can exchange the spindles based on the manufacturing process ie: steel milling vs wood carving.
Let me know if you are interested to see more capabilities of the machine.
As promised, I the next few days I am planning to add more videos in the same youtube channel, showing the precision of the machined parts and vibration data

https://youtube.com/channel/UCCArc-Er8QKMQqW0XLsU7Jg

[Andreiir]

Hi.
When i saw this tittle i was thinking lets see a nice precise and stiff , and powerful construction .
But when i saw design and the precision requirement , i was thinking WTF is precision now , or power means to people ,
i really dont get that words POWERFUL and PRECISE .
In ur world precise is 0.1 mm ?
And powerfull is some carbide tool scratching a steel sheet ?

[Zorbit]

The wobbly stacks of aluminium extrusion don't look suitable for a steel cutting machine to me.

[3d_cristian]

The wobbly stacks of aluminium extrusion don't look suitable for a steel cutting machine to me.

"The proof is in the pudding" Is it suitable now? https://www.youtube.com/channel/UCCA...XLsU7Jg/videos

[jackjr-123]

"The proof is in the pudding" Is it suitable now? https://www.youtube.com/channel/UCCA...XLsU7Jg/videos

Sorry but I'm not really sure what it proves except that it sounds terrible and the chatter is through the roof. The first culprit being probably the crappy Chinese spindle.

[mactec54]

"The proof is in the pudding" Is it suitable now? https://www.youtube.com/channel/UCCA...XLsU7Jg/videos

Wow you know you can use a Dremel tool to cut steel, many people have shown this before with there machines cutting steel, you are obvious not a machinist or you would know that what you are showing is a machine calling out for mercy, your machine build is barely up to milling aluminum, the steel cutting is a joke, even if you filled the extrusion with EG it would still not be a productive machine to mill steel, with extrusion you have the web thickness which does not change even after you fill it with EG mix, that said EG does help to dampen the machine frame but not much else in your case

Keep working at it a light weight machine to cut steel parts of any use is a tall order but not imposable Design and Material used in the build is key, Aluminum Extrusion is not one of them

[3d_cristian]

Can you post a video of a CNC using Dremel to cut steel?

[baristerbabu]

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[3d_cristian]

Hi Andreiir and Zorbit,
I have friends that invested more than $1M to buy milling machines. They are very scared that some of their jobs will be taken away from guys that invested only $10K on milling machines that are only 300Lbs and can be easily moved from shop to shop.
I am a mechanical engineer with many years of experience. Tolerances of 0.1mm or tighter are required in some industries that you can count on your fingers. Usually they are big corporations that will not work will small/medium shops.
Vibration and thermal expansion of metals are a fact of life. However, over the years, people found ways to overcome these problems and to make railroads, bridges and skyscrapers. I am not taking credit, I am just just using it as an example.
The information that I am posting are just final tests of my design with no information about how I have solve some of the issues. This way everybody can decide if they like or do not like the results based on their particular application.

[3d_cristian]

That is an excellent video, and all finding are very true, However:
- Cutting steel with a carbide tool and a router is a health hazard https://carbideprocessors.com/pages/...ety-risks.html
- It is possible to mill steel using high RPM, small drill bit size and lots of cooling:
- It will create chips so small you will have them in your skin for a long time.
- The milling feed and speed needs to be developed from scratch. That takes time and lot of broken bits. In the past I have broken so many bits that I have decided not to use anything smaller that 0.5".

My machine cuts at max. 6,000RPM and uses max. 0.827" diameter tool. I have designed the spindle assembly using an ER-32 spindle and a 4HP, 3 phase, motor. The 3 phase motor can be run on residential power using an adapter.

I have designed and build the "1st steel milling CNC made with T-Slot Extrusions"! that is NOT a HEALTH HAZARD!

[mactec54]

That is an excellent video, and all finding are very true, However:
- Cutting steel with a carbide tool and a router is a health hazard https://carbideprocessors.com/pages/...ety-risks.html

That's the best one I have ever heard, you really don't know anything about machining, carbide can only be a health hazard from the dust when Grinding it, HSS cutters have the same Health Hazard, so now you have no cutters that you could use with your cnc machine including drills, because when they are ground there grinding dust is a health hazard

You need to do some very basic reading on machining so you can understand what you are posting

- The milling feed and speed needs to be developed from scratch. That takes time and lot of broken bits. In the past I have broken so many bits

.
If you know what you are doing you never break a cutter

My machine cuts at max. 6,000RPM and uses max. 0.827" diameter tool. I have designed the spindle assembly using an ER-32 spindle and a 4HP, 3 phase, motor. The 3 phase motor can be run on residential power using an adapter.

Nothing new with doing this I have built many spindles, like this there are some posted here on the zone, ( Power adapter ) VFD Drives are what most hobby machine builders and the Chinese machine imports have to run there Spindles

The Power adapter you are referring to is called a VFD Drive

I have designed and build the "1st steel milling CNC made with T-Slot Extrusions"! that is NOT a HEALTH HAZARD

Keep Dreaming there have been many before you do this with the same type of build

[3d_cristian]

That is a very good idea Zorbit!
I did that in the following video. I just turn the spindle on before applying force to the tool:
At under 3 thousand of an inch or 0.060mm tolerance, maybe everybody should manufacture milling machines from bolted extruded aluminum.

[awerby]

There's a lot of distance between a million dollars and ten thousand. There will always be small shops with less invested capital that will be able to take on jobs that aren't economical for the bigger players. But if the job involves machining things out of steel rapidly and to a high degree of precision, I don't think your router design will cause them to lose any sleep. While boxing in the Z axis like you've done, and using side walls instead of perching the gantry on high stilts does add a certain amount of extra rigidity compared to a typical router it's not nearly enough to make this into a real milling machine. It might be able to handle aluminum to some extent, although the videos you've posted so far aren't very convincing even of that.