new at machining

General MeshCAM Questions

new at machining

Postby sspaober » Fri Jun 26, 2015 4:22 pm

cnc_help.jpg
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Helo,

I made jpg file with questions and pictures.
Please help me - I do not have any experience at machining.

Thanks,
Andrej
sspaober
 
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Re: new at machining

Postby Randy » Fri Jun 26, 2015 4:55 pm

Hi Andrej, and welcome to the forum. You are climbing two learning curves--MeshCAM and the actual machining. Fortunately they can be separated somewhat.

First of all, what machine do you have? And what is the scale of your workpiece? How wide are the strokes on your numbers? That will determine what size of cutter you can use, and the size of the cutter will determine how agressively you can cut (along with the machine stiffness, spindle speed and torque, etc.)

The STL is coming in "sideways" because of the coordinate system that the CAD program uses. (SolidWorks, for example, makes Y as upwards as standard). You will need to rotate the STL so that the "15" is facing upwards. After you load the STL, go to Geometry | Rotate Geometry and pick the side to machine that faces the same direction as your "15". Here is an example with the samplerhino that comes with MeshCAM.

rotate.png
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After you hit OK the "15" will be facing upwards.

You want to place the Program Zero in MeshCAM in the same corner of your block where you zero the X,Y,Z when you place the actual cutter. Program Zero is the only thing that links the MeshCAM coordinates to the real-world coordinates.

As long as you use a cutter that is more than half the width of the grooves, you won't need to use roughing, just parallel and pencil finsihing. You will use Machine Geometry Only and Margin=0 and check Dont' Machine Top of Stock. That way MeshCAM won't try to machine the top or side surfaces of the block, just the "15" itself.

STL is for workpieces with "3D" shapes (curved, sloping, blocks with part-depth pockets, etc.) and DXF is for "2.5D" workpieces that could be cut out of a sheet of material, with all walls vertical and all cuts all the way through the material, like a gasket or flat mounting plate etc.

Randy
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
Randy
 
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Re: new at machining

Postby sspaober » Tue Jun 30, 2015 1:17 pm

Thanks for answer.
Sorry for my late response, but I was waiting for email notification that post was putted to forum.

So I have an old EMCO F1 CNC which I retrofited with NEMA 23 stepers and planet USB CNC controler.
The spindle motor is original - very powerfull. Machine is very suitable for working with aluminium.
Machine is very solid build.

So can you give me some tables (I mean some links with it) about feed rate,... for aluminium.

About diameters of cuuters I will figure out.

Sorry, but can you explain me this again:

You want to place the Program Zero in MeshCAM in the same corner of your block where you zero the X,Y,Z when you place the actual cutter. Program Zero is the only thing that links the MeshCAM coordinates to the real-world coordinates.

So is that corect: I put program zero to same corner as I manualy et cutter on machine?

Best regards,
Andrej
sspaober
 
Posts: 4
Joined: Fri Jun 26, 2015 4:01 pm

Re: new at machining

Postby Randy » Wed Jul 01, 2015 4:05 am

sspaober wrote:So is that corect: I put program zero to same corner as I manualy et cutter on machine?


That is exactly correct, Andrej.

About the speeds and feeds, maybe other people will need to answer. Many endmill manufacturers have sample speeds and feeds, they are assuming large industrial machines. Here is a typical one

http://www.harveytool.com/cms/GeneralMa ... es_17.aspx

and here is one that is aimed more at hobby-level machines

http://littlemachineshop.com/reference/ ... hp#Milling

Randy
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
Randy
 
Posts: 1812
Joined: Wed May 14, 2008 9:50 am
Location: North Texas, USA

Re: new at machining

Postby sspaober » Tue Jul 07, 2015 10:19 am

Helo,

I still have problem about machining only cuts without machinig other sides.
I did like this:
- i made stl file with prismatic part dimensions 60*40*30 with rounded cut dim. 45*15 2 mm deep on top surface
- in mashcam V6 I set define stock with same dimensions and position xyz all set to zero
- toolpath options: machine geometry only, machine margin 0, without roughing, dont maachine top of stock,
- i pick up 10 mm end mill to do that

When I made toolpath it is always with side cutting too. And if I put file to cut viewer mill it is also cutting all side walls.
So whot I shoul do not to maching side walls?

Best regards,
Andrej
sspaober
 
Posts: 4
Joined: Fri Jun 26, 2015 4:01 pm

Re: new at machining

Postby Randy » Wed Jul 08, 2015 1:10 am

Andrej, can you upload your sample part (zip it first to attach) please? I would like to take a look at it. It sounds like you are doing everything correctly.

Randy
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
Randy
 
Posts: 1812
Joined: Wed May 14, 2008 9:50 am
Location: North Texas, USA

Re: new at machining

Postby sspaober » Wed Jul 08, 2015 2:25 pm

Helo,

this is stl file with part.
I hope you will figure out the problem,

I use mm unit.

Best regards,
Andrej
Attachments
NewZiputor_cnc1.zip
(3.5 KiB) Downloaded 209 times
sspaober
 
Posts: 4
Joined: Fri Jun 26, 2015 4:01 pm

Re: new at machining

Postby Randy » Wed Jul 08, 2015 6:02 pm

Thank you for the STL, Andrej. Here are the settings I used

parameters.png
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and here are the toolpaths

toolpath.PNG
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Be sure that you don't let MeshCAM override your zero margin setting. I think that this might be what is happening. MeshCAM always wants to machine the whole part and you need to tell it NO:

warning.PNG
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Randy
All opinions in this post are mine alone. I am not a MeshCAM employee, I do not have a financial interest in MeshCAM, nor do I speak for MeshCAM. MeshCAM user since Beta 5 in 2003. viewtopic.php?f=11&t=15333 :ugeek:
Randy
 
Posts: 1812
Joined: Wed May 14, 2008 9:50 am
Location: North Texas, USA


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