5 axis noob, how to machine this part?

[Pitka_Guru]

XXXXX.01.03 INLET TANK.MCX-7

 

 

Hello everyone. I'm new to 5 axis but I've taken in-house solutions 5axis and both mastercamU Multiaxis courses. We have a Haas VF-4ss with a TR210 trunnion. Running X8 and using the Generic Haas VF-TR_Series 5X Mill post.  

 

 

My questions are as follows. 

 

1: What is the best way to hold this part? Can this be held in a Raptor dovetail?

 

2: What toolpaths would work best for roughing and finishing this part?

 

3: Other than a lolipop for the inlet port will I need any special tools? I know of Harvey tool but what other manufacturers should I be looking at?

 

4: Anything I should look out for in regards to machine/control def and post processor settings?

 

 

I was able to upload the file as x7

 

Cheers!

[Jim at Gentex]

What is the material?

Are you making the part from a solid billet of material, or is it a casting, molded part, etc...?

 

One of the nice features of Mastercam is that there are a number of different toolpaths that can all accomplish the same result.

So it often comes down to personal preference of the programmer. 

[Colin Gilchrist]

There was a video that Karlo Apro did a while back that covered some of these questions in a general way. The gist of the video was that you should use put some simple toolpaths on the part, and use Machine Simulation to help you determine how to best hold the part. More time spent up front with figuring out the setup will really pay off' when you avoid issues like running out of machine travel, having really long overhangs on your tools, and crossing over the zero point of your axes, which can sometimes cause a part on a VF-TR to spin.

 

For holding onto the part, I would consider holding this part with a Window Frame, gripping with a dovetail onto one end of the block. That way you could kick the trunnion over at A 90 degrees, and reach all sides of the part by just spinning the platter ( B Axis).

[Pitka_Guru]

Thanks guys. The part is from a solid billet of aluminum. I've searched for an example of window framing but I'm not having much success. Any ideas where I can find some?

 

I have watched that video by Karlo Apro but I'm struggling with all of it to be honest. Any guidance is appreciated.

 

Thanks 

 

I got the file to upload as x7 as well. 

[Jim at Gentex]

One more question:

Is this a one-off part, or will you be making multiple parts?

 

That can help determine your work-holding method.

Parts like these are difficult to hold, so that is the first major hurdle you must get over before you need to worry about toolpaths and cutting tools.

 

If it's a one-off you probably won't want to spend the time and money to make an elaborate holding fixture without killing your profit margin.

If it is a 'production' part that you will make multiple times, it's much easier to justify spending time and money up front to produce hard tooling.

 

I've done many one-offs like this using this method:

 

• Start with a solid billet that is 1.5" to 2" larger all around than the finished part.
• Holding it in a vise, pick a corner of the billet for your zero point, machine one side of the part geometry, either top or bottom, making a pocket that captures the whole part and leaves 5 of the 6 outer surfaces of the billet intact.
• Fill the pocket with a urethane casting material like this:
• http://bccproducts.com/wp-content/uploads/2012/02/flyer-BC8007-BC8007-21.pdf
• Machine the top surface of the hardened casting material so it is level with the top of the billet.
• You now have 50% of your finished part captured within the billet.
• Now you can flip the billet over in the vise (top to bottom), re-establish your zero point from the corner of the billet, and machine the second side with the first side captured in the urethane.
• Once you get to final depth on the second side, cut away the remaining billet material on a bandsaw, and pop off or chip away the urethane slug.

I have used this method many times but there are a few cautions:

• The urethane material will stick to the aluminum to the point where it is difficult to remove.  I use a thin coating of car wax on the finished surfaces before pouring in the urethane.
• Remember, the 'second' side of the operation is only held inside the billet by the urethane slug, so reducing speed and feed is necessary to avoid shaking the part loose before all machining is finished.

edit: Back to tools and toolpaths...

It looks like you can do quite a bit of this with 2D surfacing toolpaths, but since you are doing it on a 5-axis you can try miltiaxis-multisurf.

I would say most of it can be done with a standard ball end mill.

You can use a lollipop cutter for that opening, but it can probably be done with a regular ball mill as long as there are no negative surfaces or undercuts.

I can't see the whole model, only the picture.

 

Good Luck! 

[crazy^millman]

One more question:

Is this a one-off part, or will you be making multiple parts?

 

That can help determine your work-holding method.

Parts like these are difficult to hold, so that is the first major hurdle you must get over before you need to worry about toolpaths and cutting tools.

 

If it's a one-off you probably won't want to spend the time and money to make an elaborate holding fixture without killing your profit margin.

If it is a 'production' part that you will make multiple times, it's much easier to justify spending time and money up front to produce hard tooling.

 

I've done many one-offs like this using this method:

 

• Start with a solid billet that is 1.5" to 2" larger all around than the finished part.
• Holding it in a vise, pick a corner of the billet for your zero point, machine one side of the part geometry, either top or bottom, making a pocket that captures the whole part and leaves 5 of the 6 outer surfaces of the billet intact.
• Fill the pocket with a urethane casting material like this:
• http://bccproducts.com/wp-content/uploads/2012/02/flyer-BC8007-BC8007-21.pdf
• Machine the top surface of the hardened casting material so it is level with the top of the billet.
• You now have 50% of your finished part captured within the billet.
• Now you can flip the billet over in the vise (top to bottom), re-establish your zero point from the corner of the billet, and machine the second side with the first side captured in the urethane.
• Once you get to final depth on the second side, cut away the remaining billet material on a bandsaw, and pop off or chip away the urethane slug.

I have used this method many times but there are a few cautions:

• The urethane material will stick to the aluminum to the point where it is difficult to remove.  I use a thin coating of car wax on the finished surfaces before pouring in the urethane.
• Remember, the 'second' side of the operation is only held inside the billet by the urethane slug, so reducing speed and feed is necessary to avoid shaking the part loose before all machining is finished.

edit: Back to tools and toolpaths...

It looks like you can do quite a bit of this with 2D surfacing toolpaths, but since you are doing it on a 5-axis you can try miltiaxis-multisurf.

I would say most of it can be done with a standard ball end mill.

You can use a lollipop cutter for that opening, but it can probably be done with a regular ball mill as long as there are no negative surfaces or undercuts.

I can't see the whole model, only the picture.

 

Good Luck! 

 

Jim Bondo works just as good as a back filler. Rice Paper Tape on the part will make it a lot easier to remove from the Bondo. Bondo loves to stick to Aluminum.

[Pitka_Guru]

Thank you very much Jim. These are 1 to 2 pieces at the most and I was able to attach the model in my First post if you'd like to take a look at it.

 

How difficult is it to remove the urethane from the part? Do you have to scrape it away or does it come off in chunks? 

 

Thanks again!

[Pitka_Guru]

WOW! Bondo, wax tape and urethane, I never would have thought of this on my own. Thanks for the help, at least I have some starting point for this.

 

Cheers! 

[Jim at Gentex]

Thank you very much Jim. These are 1 to 2 pieces at the most and I was able to attach the model in my First post if you'd like to take a look at it.

 

How difficult is it to remove the urethane from the part? Do you have to scrape it away or does it come off in chunks? 

 

Thanks again!

 

Sorry I can't look at your part as I'm still running X6.

 

As I said, the urethane does stick to the aluminum.

It will break into chunks for the most part, but it still sticks, especially in tight places.

That's why I use a thin layer of car wax or model maker's 'black wax' to help release the part.

 

Thanks, Ron for the bondo tip.

The nice part about the urethane is that it goes in as a liquid so it fills in all the little pockets and gaps.

I have also used a dovetail or t-slot cutter to make an undercut pass around the inside of the pocket if the part doesn't have too many natural features to lock it in.

 

In your case, your part has that large hole through it so that should lock in pretty good.

[Pitka_Guru]

Thanks Guys, I'm going to draw up this clamping method and see where I get. I'm sure I'll have heaps more questions shortly. Thanks again for your help fella's!

[Jim at Gentex]

Glad to help.

 

If you have further questions just ask. 

[crazy^millman]

Jim the rice paper tape is very adhesive unlike the wax so less chance of the part pulling away during the machining.

 

Javier showed me this years ago and not real easy to find since it comes from Japan.

[Jim at Gentex]

Jim the rice paper tape is very adhesive unlike the wax so less chance of the part pulling away during the machining.

 

Javier showed me this years ago and not real easy to find since it comes from Japan.

 

Yes it sounds like a great idea.

I suppose regular double-back tape might work too if you put it on the relatively flat surfaces, but I never tried it.

 

Even any kind of mold release will work too, but as you say, if it can help hold the part in place that's a good thing.

Again, if the part has natural holding features like holes or slots the urethane filler works really well.

When you mix the urethane it has the consistency of latex paint, so it flows really well into all of the little nooks.

Once it sets up it's pretty durable.

[Jim at Gentex]

OK now I can see what you mean.

 

Yeah, you may need to use the multiaxis port toolpath if you have that option.

Let me look at the model a little further and maybe I can help get you started.

[Pitka_Guru]

I'm gonna get some rice tape, sounds like it's handy to have around...Jim, we have x8 mill level 3, solids and 5axis so I can use the port toolpath.

 

When I think about putting the pocket around the part I can see where I will not be able to machine the undercut on the outside of the inlet because the pocket wall will be in the way. I'm thinking I might need to orient the part in such a way to get access to the face in question see the pic I've attached. I'm just thinking out loud here

 

Thanks!

 

[Jim at Gentex]

Yes, I came to the same conclusion.

Looks like about 25 or 30 degrees rotation looking from the right plane would be needed.

This creates a few issues in other areas on the backside, but I think that's the only way to go.

 

Also, holding this in a vise might be tricky too on that little bitty Haas rotary table.

 

If you are just learning 5 axis programming, this part is about an 8.5 on a difficulty scale of 1 to 10.

[Pitka_Guru]

LOL of course, can't start with the easy ones but I'll learn more

 

I've got another idea but not sure if it's good as there is a little fixturing involved. I could leave part oriented as is and mount it to a raptor dovetail. Mill 5 sides of the top and the bore as deep as I can go. I'll machine 2 bosses on each end of the part on the longest edge. These will be for locating and I can use them for holding down on the 2nd setup.

Then I can machine a simple square block with a pocket and two locating holes for the above bosses. Fill the block with urethane or bondo, tape up the part and locate it with the bosses. Then finish machining the bottom and the inside of the bore.

 

I'll post a few pics to see if this is a good idea or not lol. 

 

Thanks!

 

 

 

Edit: I could do the fixture on a raptor as well and here are the pics of my other option. Thanks again!

 

[Jim at Gentex]

Yes, that should work!

 

I sent a file back via email with the part rotated, but this approach looks better.

 

Machining parts like this is ALWAYS a learning experience!

[RaiderX]

LOL of course, can't start with the easy ones but I'll learn more

 

I've got another idea but not sure if it's good as there is a little fixturing involved. I could leave part oriented as is and mount it to a raptor dovetail. Mill 5 sides of the top and the bore as deep as I can go. I'll machine 2 bosses on each end of the part on the longest edge. These will be for locating and I can use them for holding down on the 2nd setup.

Then I can machine a simple square block with a pocket and two locating holes for the above bosses. Fill the block with urethane or bondo, tape up the part and locate it with the bosses. Then finish machining the bottom and the inside of the bore.

 

I'll post a few pics to see if this is a good idea or not lol. 

 

Thanks!

 

 

 

Edit: I could do the fixture on a raptor as well and here are the pics of my other option. Thanks again!

 

1st setup on raptor.JPG

pocket fixture.JPG

part located in pocket.JPG

 

I think you got a good grasp on the window frame approach. might consider hitting opposite side 1st so you dont have to create the pocket  fixture? just a thought and only glanced at it so am prob. missing something. looks like a fun part.

[Pitka_Guru]

I think you got a good grasp on the window frame approach. might consider hitting opposite side 1st so you dont have to create the pocket  fixture? just a thought and only glanced at it so am prob. missing something. looks like a fun part.

 

Thanks Raider! I'd really like to avoid fixtures so if you can take a closer look you might be able to point me in the right direction I thought of doing the opposite side first but then I get lost on how to hold it down?....And yeah, its fun just not for my first one LOL! Thank you!

[metalmansteve]

This is indeed interesting.  I apologize in advance if this is a silly question but I just never get this kind of work.  

 

On a job like this do you...

 

A )  Position the part using the trunnion, then lay 3 axis tool paths on top of it.  (repeating this sequence to reach all areas of the part)  

 

B )  Use full simultaneous 5 axis motion

 

C)  Combination of both

 

I'm guessing you do "A" to rough and "B" to finish.

 

I'm also guessing if you don't have access to a full 5 axis module you can finish the entire part using method "A"?

[Jim at Gentex]

Yes, it's a combination of both IMO.

 

Whenever I make a part like this I always try to use 2D paths where I can because they are much easier and quicker.

However when you have complex geometry there's almost always a few tough spots to reach, so you do end up using full 5 axis movement more often than not.

[RaiderX]

Thanks Raider! I'd really like to avoid fixtures so if you can take a closer look you might be able to point me in the right direction I thought of doing the opposite side first but then I get lost on how to hold it down?....And yeah, its fun just not for my first one LOL! Thank you!

I propose you machine flatest side 1st with flat material around profile and bolt-dowel locations. flip and mound to flat plate locating on flat outside established excess bolt down locating with dowels to tool plate. machine second side and tool tab off around profile.

hope this makes sense and is dependent on having plenty of excess around the profile of your part.

 

very similar approach as you were showing but does not require pocketed fixture for second side just flat plate with bolt and dowel locations.

[crazy^millman]

If you did a Raptor on the bottom of the part and window frame it with tabs then you could run the part complete and then break it free from the tabs. Like what we looked at in the Matsuura booth for the Medical parts.

 

Prep Op to Machine Raptor and then good to go.

[Jayson Kramer]

Ron, I use to use the 3m tape with the bondo. Allot of people don't get that but when you do fast Rapid prototyping it was a good tool. and I would go with Ron's last thought with a Raptor.

PS Ron thanks for dropping by the office last night. see you soon.