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Fixture Plate For Machining 4 Sides of a Part

Max Weber

Aluminum
Joined
Jun 15, 2017
I have an ongoing part I make on my VMC that has features which require machining from 4 sides of the part (4 ops).

Is making a fixture plate for this part going to be too much of a headache to be worth the effort? The part is about 4x3x2.5" and I want to have 4 pieces on the fixture (raw stock, 2nd OP, 3rd OP, 4th OP) so I always have one finished part coming off each cycle. I've tried searching for other people's fixture setups, but all I find is the typical 2 operation stuff (machine one side then flip it and deck it)

Anyone do this before and have some pics to share? Is there a better way to do this repeat work on a VMC? I'm looking at a rotary indexer for my machine that runs off a spare M code, but I'm not sure how easy that's going to be to source a compatible unit and install it. 2008 Sharp 2412 Fanuc Oi Mate MC (not true 4th capable)
WbgzhO5.png

9sovYu3.png
 
Fixturing is so part and feature specific that it is literally impossible for anyone to say yes or no. Supply a file or something and might get some better answers.


The reality is, this is more then likely doable, but how difficult it will be and time to get there are TBD.

Sent from my SM-G955U using Tapatalk
 
Is the part made from solid stock? What's the material? From what I see I could imagine making it from a heavy wall "C" extrusion if it's aluminum.

But presuming it is a part that could be made on a rotary, then coming up with a "bump switch" on a 4th axis so every bump with an endmill or probe post outputs a signal to index 90 degrees might work well.
 
If you have axcess to a rotary I have a fixture design I use for most of our parts. Basically use the stock as the fixture. I made a system for the rotary that has a set of house made retention fingers that grab a Haas pull stud and sucks it up to the face of the fixture.

In this case block number 3 would have a 5/8-11 hole drill and tapped with a 1/4 dowel hole to keep the part from rotating on the X- end. You could hit all sides then finish the deep pocket in a vice cutting away the 5/8 hole and pin hole. 4 sides in one rotary op.

Heres the drawing for the fixture so you can get an idea of what im talking about. if you want I have the Cad drawings.

Screen Shot 2020-06-21 at 10.38.29 AM.jpgScreen Shot 2020-06-21 at 10.39.41 AM.jpg

Op 10: Face, drill, and tap X+ side.
Op 20: Mount on rotary, Face X- side to finished length, Machine all features on sides 1-3.
Op 30: Remove retention knob and machine side 4 slot.

By doing it this way you have almost eliminated any chance of true position error and reduce handling time.
Just my approach though.....
 
If you have axcess to a rotary I have a fixture design I use for most of our parts. Basically use the stock as the fixture. I made a system for the rotary that has a set of house made retention fingers that grab a Haas pull stud and sucks it up to the face of the fixture.

In this case block number 3 would have a 5/8-11 hole drill and tapped with a 1/4 dowel hole to keep the part from rotating on the X- end. You could hit all sides then finish the deep pocket in a vice cutting away the 5/8 hole and pin hole. 4 sides in one rotary op.

Heres the drawing for the fixture so you can get an idea of what im talking about. if you want I have the Cad drawings.

View attachment 292208View attachment 292209

Op 10: Face, drill, and tap X+ side.
Op 20: Mount on rotary, Face X- side to finished length, Machine all features on sides 1-3.
Op 30: Remove retention knob and machine side 4 slot.

By doing it this way you have almost eliminated any chance of true position error and reduce handling time.
Just my approach though.....
I'm interested in the car for this

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Max, should be very doable, although I'd also give thought to two double vises.

What are you mounting the fixture plate on? Our fixture plates are all Orange vise delta pallets, and are quick and accurate to go on and off. And relatively inexpensive, since you can mill your own from a chunk of aluminum. And with two Orange vises side by side it's easy to throw on one or two plates and go when they're a better fit than soft jaws.

For the indexer, we have that exact same 2412 and hooked up a Haas 5C indexer that was left from another machine. It's triggered by an M code and works for what we need, but probably would not work for your application because there's no brake, so it doesn't have very good resistance to torque from milling.
 
Fixture that part on a 4th its really a good idea to go 4 different ops at a time.

just by looking at it best way I can think of if you want to run all 4 sides at once is to
put in vice cut locating face on slotted side putting in 2 bolt holes and 2 1/4" dowel pin holes.
then pop on a 4th finish all 4 sides then pop in a vise and cut out slot finishing part(which will also cut out your locating and bolt holes.)

so you end up with 3 ops which one is doing 4 sides in a 4th.

you will need a 4th with a sub plate permanently attached to your 4th then another subplate that will bolt to your part(the locating holes you put in in 1st op) then bolt that to your 4th axis subplate.

heres an example were using on a 7x10x2.250 block of alum.
Sorry about he pic but I dont do solids just wireframe, but you should get the idea.

its kinda dark.(i'll try to lighten it up later if need be)
blue is rotary,purple is permanent fixture located to 4th, green is removeable plate that you bolt the part to (brown) and to permanent fixture.



fixture1.jpg
 
I have an ongoing part I make on my VMC that has features which require machining from 4 sides of the part (4 ops).

Is making a fixture plate for this part going to be too much of a headache to be worth the effort? The part is about 4x3x2.5" and I want to have 4 pieces on the fixture (raw stock, 2nd OP, 3rd OP, 4th OP) so I always have one finished part coming off each cycle. I've tried searching for other people's fixture setups, but all I find is the typical 2 operation stuff (machine one side then flip it and deck it)

Anyone do this before and have some pics to share? Is there a better way to do this repeat work on a VMC? I'm looking at a rotary indexer for my machine that runs off a spare M code, but I'm not sure how easy that's going to be to source a compatible unit and install it. 2008 Sharp 2412 Fanuc Oi Mate MC (not true 4th capable)
WbgzhO5.png

9sovYu3.png

@Max Weber , thanks for posting this, this is a really interesting conundrum.

I think the fixture plate idea is OK / fine.

Depending on how many you have to do.

I'd be tempted to

1. Switch the order of operations (to reduce chatter / ringing of unsupported thinner features.).

2. Reduce / eliminate one set up (potentially) . in this case your setup labelled "2".



fixture operations.jpg

^^^ Click to blow up.


I'd be tempted to change the order of operations as you have it labelled to,

4, 1, 3,

So 4 to 1 would be like a conventional two sided flip, then finish up on 3.

IF I could devise a way to mill the sloped flat surface (marked "number" B :-) ) and maybe use a form tool or other milling strategy on the radius / feature marked A and A' … then one might be able to eliminate your setup 2 altogether. ? [Haven't had my Weetabix yet … so who knows .].



These days you see 'Peeps" 3D-printing (low res cheap resin) representations of partially machined parts (in various process stages / ops) to figure this stuff out, maybe even like potato block painting, (if children still do that or have an app for that), imprint them into slabs of plasticine / playdough to get a visual, mental and tactile firm "Grip" on fixture design (maybe). Heck I bet this part could be made of LEGO and imprinted into playdough ;-) at various depths and orientations to get a rough handle on fixture design.

I like Milland's idea of the 4th axis indexers that have a plunger you can hit with the end of the tool.

I think the fixture plate idea is a good exercise - especially for repeat parts.



______________________________________________________________________________________


- Further brain fart - It could be that you could design a fixture such that some of the profiles and fixture elements can be superposed on top of each other or "nested" in place. That way better part precisions and accuracies could be maintained over the machine (yielding higher localized repeatabilties),rather than moving in process parts from one end of the machine's table to the other. I.e. keep each part in process to finished part as much as you can within the machine's local coordinate system for that part, (so you'd be rotating each in process part mostly in place, so your 4, 1 and 3 fixture profiles are on-top of each other and possibly at different depths; (maybe ? - looks like you might have to rotate Op 3, 90 degrees in the horizontal plane relative to the long axis of the other setups after the first "Flip".). ~ 5 axis machining claims better part accuracy as the part is mostly machined to completion in the "sweet spot" of a machine with minimal operator intervention. However, on a three axis mill without scales the local precisions and accuracies over a 4" range should be pretty good versus moving parts op 10 to 20 to 30 in 16" ranges each time to the furthest extents of the table (as per the original scheme illustrated by Max Weber/ OP) - and also possibly at the same time eliminate a lot of probing cycles, almost zero point clamping / fixturing idea.

- Post brain fart - IF you can eliminate one set up and nest the features and profiles for fixturing each Op then theoretically you could get 4 completed parts (at a time) for opening the door of the machine three or four times and flipping parts in place. Rather having work still in process to be completed, start and end of the "Run" , 4 completed parts full cycle full ops being a smidge more efficient perhaps. That would more than compensate for time lost using a bull nose/or ball end mill on that sloped feature / contouring + different strategy on the Tricky external radii of feature A to eliminate an additional setup (2). In some 5 axis scenarios you open the door twice to top and tail one part at a time, versus your 3 axis mill scenario with a fixture plate where you have roughly one completed part for each door opening of the machine (4 parts at a time for 4 door openings , as it were). ~ 5 axis being one form of enhanced automation , but also having a lot of parts on the table of a 3 axis mill being flipped by a robot or cobot would be another approach to automation. In some instances might be nice to walk away from the machine for longer periods to work on something else maybe ?
 
Last edited:
Dang hole

@Max Weber , thanks for posting this, this is a really interesting conundrum.

I think the fixture plate idea is OK / fine.

Depending on how many you have to do.

I'd be tempted to

1. Switch the order of operations (to reduce chatter / ringing of unsupported thinner features.).

2. Reduce / eliminate one set up (potentially) . in this case your setup labelled "2".



View attachment 292269

^^^ Click to blow up.


I'd be tempted to change the order of operations as you have it labelled to,

4, 1, 3,

So 4 to 1 would be like a conventional two sided flip, then finish up on 3.

IF I could devise a way to mill the sloped flat surface (marked "number" B :-) ) and maybe use a form tool or other milling strategy on the radius / feature marked A and A' … then one might be able to eliminate your setup 2 altogether. ? [Haven't had my Weetabix yet … so who knows .].



These days you see 'Peeps" 3D-printing (low res cheap resin) representations of partially machined parts (in various process stages / ops) to figure this stuff out, maybe even like potato block painting, (if children still do that or have an app for that), imprint them into slabs of plasticine / playdough to get a visual, mental and tactile firm "Grip" on fixture design (maybe). Heck I bet this part could be made of LEGO and imprinted into playdough ;-) at various depths and orientations to get a rough handle on fixture design.

I like Milland's idea of the 4th axis indexers that have a plunger you can hit with the end of the tool.

I think the fixture plate idea is a good exercise - especially for repeat parts.



______________________________________________________________________________________


- Further brain fart - It could be that you could design a fixture such that some of the profiles and fixture elements can be superposed on top of each other or "nested" in place. That way better part precisions and accuracies could be maintained over the machine (yielding higher localized repeatabilties),rather than moving in process parts from one end of the machine's table to the other. I.e. keep each part in process to finished part as much as you can within the machine's local coordinate system for that part, (so you'd be rotating each in process part mostly in place, so your 4, 1 and 3 fixture profiles are on-top of each other and possibly at different depths; (maybe ? - looks like you might have to rotate Op 3, 90 degrees in the horizontal plane relative to the long axis of the other setups after the first "Flip".). ~ 5 axis machining claims better part accuracy as the part is mostly machined to completion in the "sweet spot" of a machine with minimal operator intervention. However, on a three axis mill without scales the local precisions and accuracies over a 4" range should be pretty good versus moving parts op 10 to 20 to 30 in 16" ranges each time to the furthest extents of the table (as per the original scheme illustrated by Max Weber/ OP) - and also possibly at the same time eliminate a lot of probing cycles, almost zero point clamping / fixturing idea.

- Post brain fart - IF you can eliminate one set up and nest the features and profiles for fixturing each Op then theoretically you could get 4 completed parts (at a time) for opening the door of the machine three or four times and flipping parts in place. Rather having work still in process to be completed, start and end of the "Run" , 4 completed parts full cycle full ops being a smidge more efficient perhaps. That would more than compensate for time lost using a bull nose/or ball end mill on that sloped feature / contouring + different strategy on the Tricky external radii of feature A to eliminate an additional setup (2). In some 5 axis scenarios you open the door twice to top and tail one part at a time, versus your 3 axis mill scenario with a fixture plate where you have roughly one completed part for each door opening of the machine (4 parts at a time for 4 door openings , as it were). ~ 5 axis being one form of enhanced automation , but also having a lot of parts on the table of a 3 axis mill being flipped by a robot or cobot would be another approach to automation. In some instances might be nice to walk away from the machine for longer periods to work on something else maybe ?


fixture operations Dang hole.jpg

Except for this one hole ^^^ … Dang (click to "blowup").

:scratchchin:

So looks like 4 setups, but those could be nested in place (mostly) to maybe give four parts at a time. Right angle head for that one hole might be PITA. I don't know if that one hole could be drilled as part of stock preparation ? If that would be referenceable ? Is that cheating ? Takes you back to three set-ups. Like others have said various bolt and hole patterns can be sacrificially machined off the part itself depending on whatever scheme of clamping and locating systems you are "fix'n" to use.

@Max Weber - the hardest "Mental visual flip" in the mind's eye (for me) is your Position 1 to position 3 but after a while , the hidden features are "seeable"
 
Don't overlook the Erickson air indexers. You only need a single Mcode output to index them. They will index 4 6 8 or 12 positions and lock quite firmly. A 400 would be big enough for that part and way more rigid than a Haas 5C, a 600 would be extra rugged. I have 4th axis machines and we still use the air indexers because they are easier and faster to setup.
 
View attachment 292287

Except for this one hole ^^^ … Dang (click to "blowup").

:scratchchin:

So looks like 4 setups, but those could be nested in place (mostly) to maybe give four parts at a time. Right angle head for that one hole might be PITA. I don't know if that one hole could be drilled as part of stock preparation ? If that would be referenceable ? Is that cheating ? Takes you back to three set-ups. Like others have said various bolt and hole patterns can be sacrificially machined off the part itself depending on whatever scheme of clamping and locating systems you are "fix'n" to use.

@Max Weber - the hardest "Mental visual flip" in the mind's eye (for me) is your Position 1 to position 3 but after a while , the hidden features are "seeable"

Yeah I think you're right that I need to reconsider the order of operations. On OP 4 I get a ton of harmonics because so much material has been removed from OP 3 that it can't absorb a heavy cut, I end up having to cut less aggressively on that OP. If I did OP 3 as the last OP then I think it would give me less grief.

I think I'm going to use a thicker pallet, something at least an inch thick, probably 2 inches thick so I can bury the toe clamps into the pallet. I'm thinking about using these mitee-bite toe clamps:
Compact Toe Clamps | Mitee-Bite Products LLC.
I figured these would hold up better on a 6061 pallet as opposed to the smaller pitbull clamps since they anchor into the pallet with a pair of bolts and the clamping mechanism runs off it's own bolt within the body of the clamp.

I suppose this also means I need to make a sub-plate in case I'd like to run other jobs on this part of the table :D
I'm considering these expansion pins for the pallets to sit on and secure to the sub plate:
Modular XYZ Xpansion(R) Pins | Mitee-Bite Products LLC.
 
Is the part made from solid stock? What's the material? From what I see I could imagine making it from a heavy wall "C" extrusion if it's aluminum.

But presuming it is a part that could be made on a rotary, then coming up with a "bump switch" on a 4th axis so every bump with an endmill or probe post outputs a signal to index 90 degrees might work well.

Yeah this is made from Solid 6061. I'd like to use a C extrusion but I haven't been able to find anything with that thick of a wall.
 
Don't overlook the Erickson air indexers. You only need a single Mcode output to index them. They will index 4 6 8 or 12 positions and lock quite firmly. A 400 would be big enough for that part and way more rigid than a Haas 5C, a 600 would be extra rugged. I have 4th axis machines and we still use the air indexers because they are easier and faster to setup.

I'd love to have one of those! I suppose I need to keep my eye out for something like this. Is there anything like this still being made new?
 
Max, should be very doable, although I'd also give thought to two double vises.

What are you mounting the fixture plate on? Our fixture plates are all Orange vise delta pallets, and are quick and accurate to go on and off. And relatively inexpensive, since you can mill your own from a chunk of aluminum. And with two Orange vises side by side it's easy to throw on one or two plates and go when they're a better fit than soft jaws.

For the indexer, we have that exact same 2412 and hooked up a Haas 5C indexer that was left from another machine. It's triggered by an M code and works for what we need, but probably would not work for your application because there's no brake, so it doesn't have very good resistance to torque from milling.

Yeah I'd definitely be willing to sacrifice less positions on a rotary for rigidity/accuracy. How's your machine been holding up? I've had to send out my servo/PSU combo unit for repair twice since owning it. Just getting everything up and running again finally. Everything else on the machine has been rock solid so it's more of a fanuc thing than anything.
 
If you have axcess to a rotary I have a fixture design I use for most of our parts. Basically use the stock as the fixture. I made a system for the rotary that has a set of house made retention fingers that grab a Haas pull stud and sucks it up to the face of the fixture.

In this case block number 3 would have a 5/8-11 hole drill and tapped with a 1/4 dowel hole to keep the part from rotating on the X- end. You could hit all sides then finish the deep pocket in a vice cutting away the 5/8 hole and pin hole. 4 sides in one rotary op.

Heres the drawing for the fixture so you can get an idea of what im talking about. if you want I have the Cad drawings.

View attachment 292208View attachment 292209

Op 10: Face, drill, and tap X+ side.
Op 20: Mount on rotary, Face X- side to finished length, Machine all features on sides 1-3.
Op 30: Remove retention knob and machine side 4 slot.

By doing it this way you have almost eliminated any chance of true position error and reduce handling time.
Just my approach though.....
Thanks! This is definitely something I will consider when I get a rotary.
 
I'd love to have one of those! I suppose I need to keep my eye out for something like this. Is there anything like this still being made new?


I don't know of anything new. I've bought several on Ebay, there are a few 600s there now. If you want a cycle completed signal returned to your control, try to get one with the limit switches attached.
 
Don't overlook the Erickson air indexers. You only need a single Mcode output to index them. They will index 4 6 8 or 12 positions and lock quite firmly. A 400 would be big enough for that part and way more rigid than a Haas 5C, a 600 would be extra rugged. I have 4th axis machines and we still use the air indexers because they are easier and faster to setup.

Did you swoop in and buy up that even dozen of them 6 weeks ago at HGR ?
 
If you have axcess to a rotary I have a fixture design I use for most of our parts. Basically use the stock as the fixture. I made a system for the rotary that has a set of house made retention fingers that grab a Haas pull stud and sucks it up to the face of the fixture.

In this case block number 3 would have a 5/8-11 hole drill and tapped with a 1/4 dowel hole to keep the part from rotating on the X- end. You could hit all sides then finish the deep pocket in a vice cutting away the 5/8 hole and pin hole. 4 sides in one rotary op.

Heres the drawing for the fixture so you can get an idea of what im talking about. if you want I have the Cad drawings.

View attachment 292208View attachment 292209

Op 10: Face, drill, and tap X+ side.
Op 20: Mount on rotary, Face X- side to finished length, Machine all features on sides 1-3.
Op 30: Remove retention knob and machine side 4 slot.

By doing it this way you have almost eliminated any chance of true position error and reduce handling time.
Just my approach though.....

That is a fantastic idea! Looking at it I'm slapping myself for not thinking that up on my own for some of the parts I make. I would need pull studs threaded 3/8" 16 which should be pretty easy to make.

I too would be interested in the cad drawings please :D
 








 
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