milling lip around bottom of item

[BrassBuilder]

Alrighty. I am beginning to like this program. I have TurboCad Pro coming but I am not sure I will be using it after playing with DolphinCad all weekend.

Anyway...my next learning cycle is to mill a lip around the bottom of a part that I am making. What is the best way to do this? Take a look at my attached drawing. The part is approximately 1" x 2" x 5/16" thick. The protrusions out the front and by the upper left and rear corners are reinforcing ribs along the bottom of the part. It will be approximately 1/16" wide and about that thick.

What is the best way to mill this? Can I tell the mill to mill down to 1/4" (leaving a 1/16" yet for the lip) and then what??? I am not sure where to go from there. Should I have the lips (or reinforcing ribs...whatever) as a separate layer? Can I set them up as their own contour? So many questions.

The attached drawing has three layers. I am working with the rocker housing layer in the blue lines for this problem.
Thanks
Mike

[MrWild]

Open it in partmasterCAD.

then click on the "NC" button.

right click on the drawing and chose contour fromthe list.

Do not chose auto complete. (If the lip had it's own layer, you could use auto complete but not with the lip and housing combined.)

You will need ro make two contours.

One of the rocker housing including the lip, and one of just the housing above the lip.

When you go to Machining, you can chose the contour you wish to machine and the depth of cut leaving materialfor your lip.

It's late tonight, but if you don't get it I'll walk you through like I did Speedy.

[metalworkz]

Hi Mike,
I am not sure if I am visualizing it correctly as I have no perspective view and not sure about dimension or depth requirements.
Is the part not symetrical? The lip does not extend to the right the same as the left side. Will the ribs go up the sides only or will they go accross the part also? How thick will the lip be? Do you want a fillet in the corner where the lips meet the side?
I think if you can use a flat end mill to do the milling down towards the top of the lip for the full width of the confour and then step over and leave enough material to machine a fillet radius with a ball nose. Then change to a ball nose and finish the fillet with that just for the toolpath along the profile where the lip meets the side. It may take 3 different toolpaths to complete and can either be done with a toolchange in the program or several different programs.

If no fillet is needed then you can mill it like you mentioned down and leave enough material to machine between the ribs etc. and have the ribs say 1/16 high. Probably 2 toolpaths could do it.

[BrassBuilder]

Hi Mike,
I am not sure if I am visualizing it correctly as I have no perspective view and not sure about dimension or depth requirements.
Is the part not symetrical? The lip does not extend to the right the same as the left side. Will the ribs go up the sides only or will they go accross the part also? How thick will the lip be? Do you want a fillet in the corner where the lips meet the side?
I think if you can use a flat end mill to do the milling down towards the top of the lip for the full width of the confour and then step over and leave enough material to machine a fillet radius with a ball nose. Then change to a ball nose and finish the fillet with that just for the toolpath along the profile where the lip meets the side. It may take 3 different toolpaths to complete and can either be done with a toolchange in the program or several different programs.

If no fillet is needed then you can mill it like you mentioned down and leave enough material to machine between the ribs etc. and have the ribs say 1/16 high. Probably 2 toolpaths could do it.

Here is a picture of the part that I am copying. It does not have to be a perfect copy of this part, but just a good representation. Although a filet would be nice where the rib meets the upright part, it is really not necessary, especially if it is going to over complicate matters. Right now, I am just lucky to get parts cut with one bit and one contour. I haven't done anything where a bit change is required in the middle of a part. Although that might be sort of good knowledge to have at sometime.

The part is not symetrical. Does that matter?

I figure 2 tool paths. One for going down to the lip (1/4") and then another for the lip itself (the last 1/16").

I'm just not sure how to tell the machine to do what I want. I am sure milling this in one piece is possible...

Thanks
Mike

[BrassBuilder]

Open it in partmasterCAD.

then click on the "NC" button.

right click on the drawing and chose contour fromthe list.

Do not chose auto complete. (If the lip had it's own layer, you could use auto complete but not with the lip and housing combined.)

You will need ro make two contours.

One of the rocker housing including the lip, and one of just the housing above the lip.

When you go to Machining, you can chose the contour you wish to machine and the depth of cut leaving materialfor your lip.

It's late tonight, but if you don't get it I'll walk you through like I did Speedy.

Interesting. This is where I started to go last night while messing around with it. I got the contour for the housing itself done up last night, but I did not go any further with it.

When I do the contour with the lip part, am I doing a contour of the rocker housing too or just the lip part? I suspect I am going around the whole outside perimeter with the contour (following the lip instead of the rocker). That seems to make sense...

I'll play around with it some more today and see what happens.

Thanks

Mike

[BrassBuilder]

I'm getting there....

I got my two contours drawn. One follows around the outside of the part and the other follows around the inside. I input my thickness of each contour. When I go to the CAM part and click on ISO VIEW, the lip part is at the top of the piece instead of the bottom. How do I reverse this?

I tried to go into VIEW NC CONTOURS in the CAD part and switch the two contours. That did not do anything.
Thanks
Mike

[metalworkz]

Hi Mike,
Make sure you have the starting depth and final depths correct for both contours.From the picture it looks like there will be a thin wall around the perimeter of the part? Also make sure the view you are looking at is the correct view for the way the part it drawn in the ISO, i.e. Top view etc.
Regards,

[BrassBuilder]

Hi Mike,
Make sure you have the starting depth and final depths correct for both contours.From the picture it looks like there will be a thin wall around the perimeter of the part? Also make sure the view you are looking at is the correct view for the way the part it drawn in the ISO, i.e. Top view etc.
Regards,

Yep. That was the problem. Got that fixed.

NOW...how do I tell the program what depth of cut for the cutter bit to take for each pass? I can generate the G-Code but it is based on one huge pass. I don't think that will work very good. I want to set up the cutter (1/8" carbide) to make around a .030 pass on each cut as it makes it way through.

Mike

[John S.]

Yep. That was the problem. Got that fixed.

NOW...how do I tell the program what depth of cut for the cutter bit to take for each pass? I can generate the G-Code but it is based on one huge pass. I don't think that will work very good. I want to set up the cutter (1/8" carbide) to make around a .030 pass on each cut as it makes it way through.

Mike

Where is a how to on drilling?

Post number 4

John S.

[MrWild]

Two ways

You can set the cutter itself up as only being able to take .030 of a cut when you make it a tool in your program.

If your endmill has say a .5" flute length and this is what you specify when you give the endmill paremeters, then when you make your contour pass, you go to the Z axis tab at the in the contour set up for your cut and set the "over ride maximum cutter depth."

I prefer to set the flute length of the cutter at the cutters real flute length, then over ride the max cut depth when seting up my contours. Others like to set max depth no matter the flute length when they set up their tooling. They feel it is a form of fail safe.

[BrassBuilder]

Where is a how to on drilling?

Post number 4

John S.

Ahhhhh....OK....I saw that and I thought it was the overall cut depth of the milling bit. I had something like .75 in there. No wonder it took one pass.
Thanks
Mike

[BrassBuilder]

Arrrrrrgh! This is impossible!

OK....I finally got my drawing converted to code using the Mach3 post processor. But the code is for a whole bunch of huge circles. I cannot even see my part in there. What the heck did I do wrong? When I run the Animate thing in DolphinCAM, it looks right.

I am attaching my drawing (DXF file) and code file. I had to change my code file to a txt file so that I could upload it.

Can someone see what I did wrong?
Thanks
Mike