PDA

View Full Version : Help Please for Moving Gantry



endlasuresh
28-10-2017, 09:05 AM
Hii please help me to build My CNC milling machine.
I am not a fully machinist designer so I am getting confuse in building a CNC machine.
I was watching a lot from past 2 years, however coming to any poster they wouldn't provide full details in their threads.

Can somebody provide a open source of DIY Moving gantry for Metal milling.


I am making on the Table for 31 inches into 71 inches with 50 MM square pole, thickness of 5 or 6mm


This looking easier to build, but doesit can handle for milling metal?
http://www.mycncuk.com/threads/11358-My-CNC-300%2A440-for-processing-aluminum-alloys-and-hardwoods

Mods, please move thread if this is not right section.

endlasuresh
29-10-2017, 04:26 AM
Still no replies,
I had designed the base will post here tomorow and looking to buy rails offline. Can somebody recommend me the best rails for me?

Nr1madman
29-10-2017, 05:49 AM
Hello!

What metall do you want to mill? Steel?

50mm steel square for the base is to small I think.. I have 50mm for my planned mostly wood router (with some 80x120 6mm thickness in there ). It will never mill steel
... Also I have 6mm thickness I think..
Usually people recommend 80x80 with atleast 3mm thickness for router capable of routing aluminium.

For your rail question it depends on how the machine looks and how heavy it is.
Usually 20mm square linear rail is recommended. But it you plan on a monstermachine capable of milling 100mm thick steel it may be a different world altogether :)

Post your design an listen to advice before ordering parts. It might save you some money in the end

Skickat från min SM-N910C via Tapatalk

routercnc
29-10-2017, 09:59 AM
Most people would recommend a mill style machine for cutting steel as it is possible to build a much stiffer machine as the Z axis is grounded to the base. But there is a limit to the footprint fore aft that it can cut.
Then a gantry machine makes more sense as it can cut much larger pieces but to machine steel it needs to be well built.
The one you linked to looks like a fine general machine but it would not be recommend for steel. Everything needs to be much stiffer including using big profile linear rails not supported round rails etc

I can't remember seeing a gantry machine on this forum designed just for steel so you are not getting much direct advice.

Clive S
29-10-2017, 05:56 PM
I can't remember seeing a gantry machine on this forum designed just for steel so you are not getting much direct advice.

Hoe about Chaz's machine with the concrete gantry

routercnc
29-10-2017, 07:18 PM
Hi Clive I meant moving gantry but yes I had forgotten about Chaz's machine which will cut steel.

Endlasuresh
Have a look in the build log at Chaz's machine to see how he approached it. I'm sure this is not what you had in mind but what you can take from this is just how stiff and heavy the machine needs to be for steel

endlasuresh
31-10-2017, 07:42 PM
Thanks for all replies, here is my answers for your questions.
@Nr1madman
1. The steel would be EN 8 to EN 31 plates.
2. Ill got with 100 mm Square poles with 5 or 6 mm thickness
3. Ill go with 20 or 30mm square rails as per your suggestion but will post design soon.
4. I made the design in simple base not fully, but thinking to go with Fixed Gantry.

@routercnc

I think you are saying mill style machine that I believe fixed gantry. CAn I got with Wade O Design?
Someone suggested for moving gantry in CNC zone forums few years back, but they never replied again and never made anything.

Yeah got it what you said yes I am too loking more stiffer than the one I linked, but the design is so easy to process.

I also checked Chaz design but looks it is a fixed gantry. http://www.mycncuk.com/threads/9616-Thor-or-should-that-be-Zeus
Is this is the machine that you are talking about it?

Let me know whether I should go with Wade O design as it is easier to make and i will modify according to our need.

endlasuresh
01-11-2017, 11:28 AM
Here is the link a long back 7 years ago this guy recommended me for Moving Gantry, but till today I did nothing.
http://www.cnczone.com/forums/diy-cnc-router-table-machines/117789-cnc-post864638.html#post864638

The guy told moving gantry because for the wieghtage of milling plate. I am looking the easiest method to build it.

Nr1madman
01-11-2017, 12:50 PM
Hello again..
Just to make it more clear.
Do you want to mill or engrave steel?

Skickat från min SM-N910C via Tapatalk

endlasuresh
01-11-2017, 12:56 PM
For milling, mostly will be used for Plastic Molding Dies. Thanks again.

Nr1madman
01-11-2017, 01:03 PM
Okey :)

I think fixed gantry will be a good choice.
Maybe something like this.
https://m.youtube.com/watch?v=K9UA9ZRFwWU

I also think it's a good choice to go up in size for the steel frame.. as you have planned now!

Skickat från min SM-N910C via Tapatalk

endlasuresh
06-11-2017, 07:17 PM
Thanks for the Video and I watched it long back, planned to mAke similar one with less in size because of grinding and milling can need on z axis.
anyway here are some questions
I need size of rails and screws

For z axis 20mm linear rails can be ok?
and lead screw how much size should i take?

sample one here https://www.ebay.com/itm/Z-Axis-Linear-Rail-Bar-Shaft-100-300mm-8mm-Lead-Rod-Screw-Nut/401111615744?hash=item5d641d8900:m:m_OUnfsIjwwW4n3 8Qfo6T7g


for x and y axis should i increase 20 to 40mm?
also the same lead screw sizes as the weight would be more sometimes.

First i am going to buy these two things then build the base since these are available in Our local stores.

Waiting for your answer and the size of the base would be 31 inches into 31 or 35 inches sine I dont need the biggest onE presently.

Nr1madman
06-11-2017, 08:46 PM
Thanks for the Video and I watched it long back, planned to mAke similar one with less in size because of grinding and milling can need on z axis.
anyway here are some questions
I need size of rails and screws

For z axis 20mm linear rails can be ok?
and lead screw how much size should i take?

sample one here https://www.ebay.com/itm/Z-Axis-Linear-Rail-Bar-Shaft-100-300mm-8mm-Lead-Rod-Screw-Nut/401111615744?hash=item5d641d8900:m:m_OUnfsIjwwW4n3 8Qfo6T7g


for x and y axis should i increase 20 to 40mm?
also the same lead screw sizes as the weight would be more sometimes.

First i am going to buy these two things then build the base since these are available in Our local stores.

Waiting for your answer and the size of the base would be 31 inches into 31 or 35 inches sine I dont need the biggest onE presently.Hello again!

That ebay link is for a lead screw with 8mm thickness.. it's not nearly enough.
It probably would work for a machine made in MDF for sole purpose of machining plastic or something like that.
Not for steel construction with high weight.

Most people use ballscrews with 16mm diameter with your size machine.
Leadscrews have bigger backlash and more wear that ballscrews. And they require bigger motors.

When you say 20mm rail. What type of rail are you looking at ?

Skickat från min SM-N910C via Tapatalk

endlasuresh
07-11-2017, 11:33 AM
That lead screw was posted as sample, yes it is very small. can I use 16mm or above with ball screws.

For rails someone suggested long back linear rails. let me know the best one and sizes so i can search in market as they are available here.

thanks again,

routercnc
07-11-2017, 07:28 PM
Hi Endlasuresh,

You are only getting answers to some of your questions because what you want to do is not the usual DIY machine.

The requirements of your machine are to be able to machine tool steel (?) to create accurate dies for a plastic injection molding machine. I assume on a fairly regular / daily basis as part of a small business. This is quite an ask for a simple DIY machine and is one of the reasons you are not get a direct answer.

So, lets put it another way. No-one is going to give you plans or CAD drawings for a machine ready for you to put it together and start machining.
Instead, if I was doing what you were doing I would look at how the commercial machines go about doing it, ask yourself why they did that, and design in some of those features as best you can. For example, here is the inside of a Mori Seki machining centre with a moving gantry.

23160

23161

If you go to their website it will most likely tell you the interior cutting area and from that you can approximate the scale of the ballscrews (I would estimate at least 20 mm) and linear profile rails (estimate at least 25 mm possible larger), aligned to a reference edge and stiffened using side load 'fingers', with cast main assemblies, and a very powerful spindle, plus servos motors to drive it all. Given you started looking at machines in 2010 these sorts of features should be familiar to you.

Alternatively there you can convert a reasonably sized milling machine to CNC / buy an aftermarket kit for a milling machine. This gives you a fixed head and moving table.

Hope this helps you decide what to do - I don't think anyone on this forum is 'holding out on you' if that is the sub-text of your posts.

endlasuresh
08-11-2017, 12:15 PM
@routErcnC
I know no one is going to give cad or whole Help, but just needed some help, the rest will be done By ourselves.

thanks for your suggestions

ill go with 20mm ball S Crews and 30mm linear rails.

ill search In the market and post the images, until that i Put hold.

well all people design first and then Look for the materials, but i am Trying to find these two t Hings Offline and then design it.

the One video posted by nr i madman is easier to build so ill go with that one.

i Understand what you said, but i Want to do Once in My Life.