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D-man
02-11-2010, 02:29 PM
Im looking for some good people to help me with a project that im going to be making.

I currently own a Swimming pool filtration company and we deal with alot of under drain systems for the swimming pool filters.
The underdrain systems are built using 2 x 160mmOD PVC-U pipe ranging from 2ft per side up to 5ft per side, however most of the customers want to spice thing up a bit by making them bigger or changing the design, so we will just stick with those sizes for now. The two halfs are then glued into a 160mmID PVC T peice to make one unit.

In each half there is a number of holes that some 1,1/2" sockets are then welded into. these holes are then also mirrored on the opposite side of the pipe for each end of the socket to stick out of.

I would like help to try and come up with some design or use an already proven plan that may be available.

What should the router/profiler do?
The machine should be able to cut rounded holes along the center of the pipe (any kind of shape really). then the machine should be able to spin the pipe around and mirror the holes on the opposite sides, perfectly aligning with the opposite holes.

we do a different range of underdrain systems so the pipe fitting must be able to accept a pipe from 1,1/2" up to 8"

Hardware i have
Nema 23 motors x 3
drivers x 3
controller
supported round rail x 4
bearings x 8
ball screws x 4
lead screws x 4

all i really need to come up with is some sort of design. im guessing the design does not have to be wide, just wide enough to accept the largest bore pipe i will be putting into her. And for length im going to keep it simple and go for 5ft

any help getting me started on this project would be greatly appreciated

please see diagram

m_c
02-11-2010, 09:49 PM
I'll start of with some thoughts on this.
Drilling forces should be pretty low in PVC, and given that you'r doing this by hand just now, accuracy doesn't need to be the top of the priority list?

First idea -
To keep costs low, I'm thinking a long bench, and use some standard steel/alu for rails for a moving head to run on, driven by either a rack and pinion set-up, or for more accuracy, a timing belt (single length, anchored at each end, with it looped up and around drive/idler pulleys on the head). Other option is ball screws, but I'm guessing 6m+ ones may be quite expensive..
As you'll only be dealing with round pipe, you only need an x-axis.
Then have a rotary table at the end of the bench, which clamps the pipe, and some form of adjustable guide on the head itself to support the pipe during drilling/slotting, yet still allow the pipe to pass through/spin.

second idea -
Have the machining head static, and then have the pipe pass through it, however it would probably take a fair bit of experimenting to design some form of reliable feeding mechanism.

D-man
02-11-2010, 11:47 PM
Thanks for the replay m_c

looking back on the thread i have not really explained myself properly so here is a more detailed version


Im looking for some good people to help me with a project that im going to be making.

I currently own a Swimming pool filtration company and we deal with alot of under drain systems for the swimming pool filters.
The underdrain systems are built using 2 x 160mmOD PVC-U pipe ranging from 2ft per side up to 5ft per side, however most of the customers want to spice thing up a bit by making them bigger or changing the design, so we will just stick with those sizes for now. The two halfs are then glued into a 160mmID PVC T peice to make one unit.

In each half there is a number of holes that some 1,1/2" sockets are then welded into. these holes are then also mirrored on the opposite side of the pipe for each end of the socket to stick out of.

I would like help to try and come up with some design or use an already proven plan that may be available.

What should the router/profiler do?
The machine should be able to cut rounded holes along the center of the pipe (any kind of shape really). then the machine should be able to spin the pipe around and mirror the holes on the opposite sides, perfectly aligning with the opposite holes.

we do a different range of underdrain systems so the pipe fitting must be able to accept a pipe from 1,1/2" up to 8"

Hardware i have
Nema 23 motors x 3
drivers x 3
controller
supported round rail x 4
bearings x 8
ball screws x 4
lead screws x 4

all i really need to come up with is some sort of design. im guessing the design does not have to be wide, just wide enough to accept the largest bore pipe i will be putting into her. And for length im going to keep it simple and go for 5ft

any help getting me started on this project would be greatly appreciated

please see diagram

D-man
03-11-2010, 08:23 AM
well im very suprised at this forum.. with 95 views and still only one good fellow replyed. i thought this may of been of some interest as it something a little different, obviously i was wrong

Wobblybootie
03-11-2010, 09:46 AM
I have not yet finished my own build so can only give my ideas which are not based on experience ... I concur with M-C A moving gantry using belt drive (an Omega drive I think). Unless you have shed loads of space I would stick with the moving gantry,as the overall footprint would be shorter. A lead screw Z Axis should do nicely with an Belt drive A Axis to turn the stock just like a low speed lathe. To support the stock maybe some form of ball or roller bearings in a gutter shaped trough below the spindle which could be made to support assorted sizes of pipe, rather than have it 'floating' supported only by the 'headstock and tailstock'. perhaps cone shaped 'plugs could be used to 'jam' the pipe between centres holding it tight enough to secure it but without distorting it.

Just a few thoughts ... I would be very interested in your progress with this, so I shall watch this space ...

I seem to remember on the MechMate Forum a guy built his machine very long to enable him to manufacture the columns so popular with our American cousins ... I think his name may have been Art Ransome ... I will try and hunt it out when I have a few minutes.

HiltonSteve
03-11-2010, 10:19 AM
MC,

I have just been thinking about what you are trying to do and I think that you could do it with a fairly simple design.....

What I am thinking is that you will only need 3 directions of movement, Rotary (A) to spin the pipe, Linear (X) to move along the pipe and Vertical (Z) to plunge the cutter. You could even do away with the Z axis being controlled by steppers and do it manually seeing as you are only cutting through pipe, just a thought.

With a max pipe dia of 8" then why not limit the travel on the X axis (along the pipe) to something similar, maybe 10"-12" will do. Moving along the pipe to cut various other holes could be done with a second linear move and clamp system that could be positioned manually anywhere along a 5ft pipe.

Your design then could consist of a fairly small X axis which could be done with a ballscrew as you will only need a small amount of travel. Same goes for the Z axis (if you go for stepper control), use a manual move and clamp method to get it close to the pipe surface depending on the pipe dia and then you will only have a small distance to go to plunge through the pipe.

Pipe would be held at one end by a chuck which is controlled by a stepper motor for rotation and by a simple 3 roller type system at the other, 2 at the bottom which again have a manual height adjustment for various dia pipe and one roller at the top to hold it on place.

Hope that makes sense, trying to dip a hobnob in my tea at the same time as typing this is a bit distracting.

Have a look at the photo below then read my post again, may make a bit more sense!

D-man
03-11-2010, 02:57 PM
Thanks guys,

Here is an image that i was thinking of, sorry i cant use CAD to create the fancy images you guys do, so go easy on me lol

m_c
03-11-2010, 03:14 PM
That extra info is good!

For the drilling, you need an A-axis, if you want the material turned automatically. To begin with, as you're only drilling holes on opposite sides, you could always just rely on turning the pipe by hand (machine drills/machines one side, then spin the pipe 180deg and let it do the other side).

However, now that I know the type/size of holes you're doing, a x and y axis is pretty much essential.
For the bigger holes, in order to keep the edges parallel, you either need to use a milling cutter and move the work under the cutter, which requires 3 way movent (up/down, fore/aft, right/left), or to rely on having the correct sized cutter so the pipe remains stationary.

The hardest part I'd say to design, will be some form of clamp/support for the pipe. Rotary table at one end with chuck to control rotation of pipe, then on the moving head, some form of roller/guide assembly on the head to support the pipe at the cutter (probably one either side of the cutter for maximum support).

HiltonSteve
03-11-2010, 03:32 PM
Just check this video out, it shows what I was trying to explain....

The interesting stuff starts around the 2 min mark, cutting large holes with a plasma, for your design the plasma would be replaced with a small router or Kress with something like a 6mm slot drill. Also it shows the machine drilling holes with a standard drill bit.

Same principle as I was trying to explain though, just an X axis to travel along the centreline of the pipe, an A axis to rotate it and a Z to plunge through, Z would be optional but nice to have! Not sure why you would need a Y axis at all??

You could also cut the ends of pipes so you can create your own 90 degree joints.

Simples....!


http://www.youtube.com/watch?v=CS719RGNCZg

m_c
03-11-2010, 03:47 PM
You'd need a y to keep the cut edges parallel for slotting the cross pipe in.
If you rely on spinning the pipe to create the hole, the edges are always going to be half the cutter width of the centre line, creating an unequally chamfered hole. For small holes, or thin pipe, it's not too much of an issue, but if you're needing a tight fit, you really need to use a y-axis to keep all edges parallel.

D-man
03-11-2010, 03:51 PM
Thats perfect steve!!!

thats exactly the sort of thing i need but without all the bells and whistles! lol but where to start..

Where can i find a cheap chuck? rotary head?

m_c
03-11-2010, 04:05 PM
I'd almost suggest some kind of custom rotary head.

A rotary table seems like overkill for machining plastic, but is probably the easier option.

I'd think a more basic axle with clamping head, driven by either a gear reduction stepper or double belt reduction would provide enough torque/accuracy, and be far quicker at spinning the pipe.

The clamping head/chuck could be a challenge, as you can't really put too much pressure onto PVC pipe. Perhaps some sort of metal plug for each pipe size bolted to the rotary head to support the inside of the pipe and prevent it collapsing in, then jaws which clamp down onto the outside. The big issue is covering the range of pipe sizes, while not making it too hard to swap between sizes.
Perhaps have the centre plug held on with a centre bolt, then jaws, or even a big pipe clamp to clamp the pipe onto the centre plug.

D-man
03-11-2010, 04:09 PM
I see what your saying M_C

the only way time the cut will be verticle is when the router is at the top of the pipe. but when the pipe rotates when the side of the hole is put back into position it will be on an angle.. correct see diagram.

where as if i have an extra axis the router bit will stay vertical all the way around the hole

Does this make sense?