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Discussion Starter · #1 · (Edited)
Hi, I figured this might be a good place to ask about my thickness planer.
I'm starting a business with my brother and we've been chasing this issue for months now, it's preventing us from actually starting to work, since it completely ruins the piece...

The problem we're chasing is a random leading edge chipping that destroys the plastic pieces.
I'll attach pictures and a video showing my problem.

Installed helical cutter head.



Picture of a severely damaged piece.


Here's a video where you can see the plastic going in and planing good the first couple of times, then randomly the leading edge gets chipped at 0:38 seconds.

After thinking how to mitigate the problem I made a guide bar to support the pieces going thru the planer to reduce bowing before the cutting head, hopefully this eliminates the chipping.




I'll be installing the guide bar today and see how it works...

Any input and help is very much appreciated!
 

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Alan - welcome to the forum, what part of the world are you in ?

are you a hobbyist or commercial business ?
and, what project are you working on that requires plastic to be run through a planer ?

.
 

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Discussion Starter · #3 · (Edited)
Alan - welcome to the forum, what part of the world are you in ?

are you a hobbyist or commercial business ?
and, what project are you working on that requires plastic to be run through a planer ?

.
Hi John, thank you. I'm in Las Vegas, Nevada, USA.
We, my brother and I, are trying to start a commercial business but with the current issue (chipping leading edge) we can't even begin to work because we would destroy all the boards we put thru the machine.

We want to start planing plastic cutting boards for kitchens, that way there's always a fresh smooth surface that prevents bacteria from collecting.
 

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I've never run plastic through a planer but I can see what is happening. It's called snipe. You have an infeed roller and an outfeed roller in the planer. When the plastic is under both there isn't a problem but when it leaves the infeed roller the plastic raises up a little, just enough to chew it up. It does it on wood too but not as noticeable. What you would need to do is raise up the end of the plastic that has come through the planer so it stays flat on the table. This can happen on the infeed too. The material needs to be flat on the planer table all the way though. You may also have bottom rollers on the planer that may be too high and holds the material up off the table. The bottom rollers are suppose to be almost flat with the table. Just raised maybe a thousandth of an inch. It's there just to keep the feed rollers from bending the material downwards.

If you are going to be doing a lot of this I would suggest using a timesaver sander. I know they are expensive but would give you a lot less problems.
 

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the work pc is thin enough it is being 'bowed' by the pressure of the feed rollers.
it's plastic, it bends.


super ultra light cuts might help - but that's going to be more time = < $$ for the service.
given the cost of 'plastic cutting boards' - this could be a lose-lose-lose endeavor - especially if there's shipping involved.



you could also try a sled - the side/back rails will be sacrificial and required 'new' thickness rails for every piece....
 

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Discussion Starter · #6 ·
I've never run plastic through a planer but I can see what is happening. It's called snipe. You have an infeed roller and an outfeed roller in the planer. When the plastic is under both there isn't a problem but when it leaves the infeed roller the plastic raises up a little, just enough to chew it up. It does it on wood too but not as noticeable. What you would need to do is raise up the end of the plastic that has come through the planer so it stays flat on the table. This can happen on the infeed too. The material needs to be flat on the planer table all the way though. You may also have bottom rollers on the planer that may be too high and holds the material up off the table. The bottom rollers are suppose to be almost flat with the table. Just raised maybe a thousandth of an inch. It's there just to keep the feed rollers from bending the material downwards.

If you are going to be doing a lot of this I would suggest using a timesaver sander. I know they are expensive but would give you a lot less problems.
Hi Steve, thanks for the comments.
I don't have any snipe on the trailing edge, it's super smooth. The problem is it gets chewed/chipped/sniped only at the leading edge. I tried giving the rollers more pressure and less pressure, it seems to not affect the outcome at all, pther than some scuff marks from the rollers themselves on the boards when I increase the pressure.
I'm sorting out the chain drive now, since I can't route it how it normally was anymore when I added the support bar I made. Hopefully I can mitigate this snipe issue with that piece.
I also don't have roller on the table, it's all steel, so that's not where my problem lays.
And about the sander, I can't use it because the plastic melts and it clogs the sanding drums unfortunately.

Thanks again for the comments and help!

the work pc is thin enough it is being 'bowed' by the pressure of the feed rollers.
it's plastic, it bends.


super ultra light cuts might help - but that's going to be more time = < $$ for the service.
given the cost of 'plastic cutting boards' - this could be a lose-lose-lose endeavor - especially if there's shipping involved.



you could also try a sled - the side/back rails will be sacrificial and required 'new' thickness rails for every piece....
Hi Tom, thanks for the comments.
The customers will be giving me bowed and deformed boards every day, so I kind of need the rollers to put pressure on the piece to make it flat for planing but I do see that if I put too much pressure they could bow up and cause my gnarly snipe problem.
I've tried doing super light cuts and it becomes an endless job on that single board, also my regular cuts are less than 10 thou already.
Regarding the cost, I've set my pricing at around half the cost of a new board, so it's encouraging for customers to resurface their boards, when physically possible.
And the sacrificial sled/pieces would not be cost effective nor healthy for the inserts on the cutting head, as the super aggressive snipe would still occur and I highly doubt that's any good lol.

Thanks for the comments!
 

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I have purchased 3/4 and 1" thick restaurant cutting boards at my local flea market
that were in very bad shape from years of heavy use. I know the 1" boards
would see many more years of use if they were planed down below the damage.
I see your point - and I see a market for it.
are you seeing the same damage with the same size wooden boards ??

.
 

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Discussion Starter · #8 ·
I have purchased 3/4 and 1" thick restaurant cutting boards at my local flea market
that were in very bad shape from years of heavy use. I know the 1" boards
would see many more years of use if they were planed down below the damage.
I see your point - and I see a market for it.
are you seeing the same damage with the same size wooden boards ??

.
I have not tried any wooden boards yet, I should buy some for testing and see how that goes.
 

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It's still snipe on the lead in. For what ever reason the plastic is raising up until it gets to the outfeed rollers. If you would raise up the rear end of the panel until it reaches the outfeed rollers it should fix the problem. By raising up the rear end you end up putting down pressure on the front end.
 

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Discussion Starter · #10 ·
It's still snipe on the lead in. For what ever reason the plastic is raising up until it gets to the outfeed rollers. If you would raise up the rear end of the panel until it reaches the outfeed rollers it should fix the problem. By raising up the rear end you end up putting down pressure on the front end.
I'll make the feed table inclined once its all together again, but I don't think this extreme snipe is going to get fixed by lifting the board as it goes in.
I'm struggling with the chain drive now, I can't find a way to route it without having contact with other parts.

The other company that does plastic resurfacing also has a thickness planer but they don't have the problems i'm having with this severe sniping. They just throw all the boards into the planer and it works perfectly, no matter how deformed the boards are... I don't know what it is, I really hope the support bar fixes it...
 

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I've got an old Newman 24" planer which there is probably a little more than a foot between the feed rollers. I have difficulty with snipe on both ends if I don't raise the material up when it doesn't have both feed rollers on it and that is on wood. I think plastic which is probably more flexible would tend to grab making it worse. It may be you will have to take less off per pass with the planer you have.
 

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I used to do this now and then for a guy with a leather craft business. He die cut leather in a press, and the plastic backer board needed resurfacing from time to time. I had a straight knife Yates American planer with hss knives. I knew the plastic would be rough on them; so I'd call him just before they were sharpened, and they would be the last cuts the knives would make before I pulled them. I ran the plastic boards on an oversized mdf backer board and at angle so the start of the cut just caught a corner first. Flatness was important since he wanted his cutting dies to just kiss the plastic backer when they cut through the leather. I never had a problem with this.

I am a bit puzzled looking at your planer. I don't see either a chip breaker on the infeed side of the cutterhead or a pressure bar on the outfeed, just the top feed rolls. What you are calling a "guide bar" looks like a solid chip breaker to me. Am I missing something?
 

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Discussion Starter · #13 ·
I used to do this now and then for a guy with a leather craft business. He die cut leather in a press, and the plastic backer board needed resurfacing from time to time. I had a straight knife Yates American planer with hss knives. I knew the plastic would be rough on them; so I'd call him just before they were sharpened, and they would be the last cuts the knives would make before I pulled them. I ran the plastic boards on an oversized mdf backer board and at angle so the start of the cut just caught a corner first. Flatness was important since he wanted his cutting dies to just kiss the plastic backer when they cut through the leather. I never had a problem with this.

I am a bit puzzled looking at your planer. I don't see either a chip breaker on the infeed side of the cutterhead or a pressure bar on the outfeed, just the top feed rolls. What you are calling a "guide bar" looks like a solid chip breaker to me. Am I missing something?
Hi John, sorry about the incorrect terminology, I'm new to these machines.
Yes, the big piece that I called guide bar is in fact a chip breaker and I the machine came without a pressure bar on the outfeed, it only had it on the infeed.
I ended up removing the infeed pressure bar to replace it with the chip breaker and it seems to be working fine for the moment. I will continue planing the plastic boards and see how it does.

Here's some videos of the planer working with the chip breaker in place of the infeed pressure bar.


 

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Try blowing out the chips (debris) before placing the board on top of them. Placing the board on top of the chips will change the amount being taken off in each pass. This would only show up on the leading edge as it clears the chips as it goes through.

Tim
 

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Discussion Starter · #15 ·
Try blowing out the chips (debris) before placing the board on top of them. Placing the board on top of the chips will change the amount being taken off in each pass. This would only show up on the leading edge as it clears the chips as it goes through.

Tim
Hi Tim, the debris produced is super thin, I'd say less than 5 thou, and they get blown away by the cutting head as soon as the board comes out.
I'll also install a shop vac to collect everything once it's all set up.
 

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Hi Tim, the debris produced is super thin, I'd say less than 5 thou, and they get blown away by the cutting head as soon as the board comes out.
I'll also install a shop vac to collect everything once it's all set up.
If you watch the first video closely, the chips are not cleared on the pass that has the problem. The pass before the problem, as you set the edge down, it sweeps the debris ahead of the cut. On the pass that has the issue, there are some chips that gets trapped under the corner of the board. I'm not sure how much you are taking off in each pass, but say it's a 1/64 of an inch. That's about 16 thousands. So add this to the 1/64 your taking off in the lapped pass and it's 1/32nd. But it's actually more than this, since the chips are not laying flat, but are curled and the point at which the board is being lifted is not at the edge. It's a fulcrum that will magnify the difference a little bit more.

There is a slight difference in chips created by a spiral cutter and straight knives, straight knives I find it easier to clear the shavings, but I love the results from the helical head. I have no experience with a spiral cutter, but I would expect it to be very similar to the helical cutter. If the small cutters take too big of a cut, they can dig in and lift the edge (flexing the plastic) as they bite deeper.

In any event, take some more video, it's a great tool... use it to look for the differences between the passes that work and those that have issues. It may be something small, for instance look at the difference in how you are feeding it or which edge left/right the board is closest to. I have found on my thickness planer, it is effected by the angle I start and finish the boards at. To reduce the amount of snipe, I set up a table for in feed and out feed, then slide it directly from the table into the planer. That way it always enters and leaves at the same angle relative to the bed under the cutter.

Of 'course I am assuming the cutter was installed correctly, that it measures the same amount off the deck on the left and right sides. This is tougher to do on helical cutters over the other two as the knife angles change depending on where on the head you are.

FWIW, to me from the picture, it looks like you have a spiral head and not a helical head, as the knives are all in the same orientation. That's why I keep referring to it as a spiral cutting head.

Tim
 

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i agree with steve, the table rollers are raising the front end of the board, into the cutterhead. we have a similar machine.

3 things to try.
lower the table rollers to level or below the table, we have to do this with thin wood. normal roller height .002 - .003 above table.
always angle the part through the machine.
try riding the board throgh on a (flat) plywood sled.

the planer may not be your best machine for this application.
 

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Discussion Starter · #18 · (Edited)
If you watch the first video closely, the chips are not cleared on the pass that has the problem. The pass before the problem, as you set the edge down, it sweeps the debris ahead of the cut. On the pass that has the issue, there are some chips that gets trapped under the corner of the board. I'm not sure how much you are taking off in each pass, but say it's a 1/64 of an inch. That's about 16 thousands. So add this to the 1/64 your taking off in the lapped pass and it's 1/32nd. But it's actually more than this, since the chips are not laying flat, but are curled and the point at which the board is being lifted is not at the edge. It's a fulcrum that will magnify the difference a little bit more.

There is a slight difference in chips created by a spiral cutter and straight knives, straight knives I find it easier to clear the shavings, but I love the results from the helical head. I have no experience with a spiral cutter, but I would expect it to be very similar to the helical cutter. If the small cutters take too big of a cut, they can dig in and lift the edge (flexing the plastic) as they bite deeper.

In any event, take some more video, it's a great tool... use it to look for the differences between the passes that work and those that have issues. It may be something small, for instance look at the difference in how you are feeding it or which edge left/right the board is closest to. I have found on my thickness planer, it is effected by the angle I start and finish the boards at. To reduce the amount of snipe, I set up a table for in feed and out feed, then slide it directly from the table into the planer. That way it always enters and leaves at the same angle relative to the bed under the cutter.

Of 'course I am assuming the cutter was installed correctly, that it measures the same amount off the deck on the left and right sides. This is tougher to do on helical cutters over the other two as the knife angles change depending on where on the head you are.

FWIW, to me from the picture, it looks like you have a spiral head and not a helical head, as the knives are all in the same orientation. That's why I keep referring to it as a spiral cutting head.

Tim
Hi Tim,
You're right, I just noticed on the first video that there's some chips that are under the board when it passes. I'll be super careful on every pass from now on not to trap anything under the boards.
I think I have mitigated the problem now tho, the chip breaker has been working great and I haven't had the extreme snipe problem.

Regarding the cutting head, I apologize for using incorrect terminology, it's my first owning and using this equipment.


i agree with steve, the table rollers are raising the front end of the board, into the cutterhead. we have a similar machine.

3 things to try.
lower the table rollers to level or below the table, we have to do this with thin wood. normal roller height .002 - .003 above table.
always angle the part through the machine.
try riding the board throgh on a (flat) plywood sled.

the planer may not be your best machine for this application.
The raising problem seems to have been fixed with the chip breaker I added, I might add a pressure bar after the cutting head to help with trailing snipe in the future.
I'll see if I can make a sled to use on the boards, the only problem that I see with the sled is that all the boards I'll be servicing are different sizes, there's no standard.

And regarding the planer not being my best bet, I don't think there's another way to do this. All the plastic resurfacing companies use a thickness planer to do the job.
I was recommended a sander by another member, but the sanding drums get clogged and the plastic also melts making it a nightmare to use and possibly also ruining the boards.



Thanks for all the comments and suggestions! :)
 

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i would investigate what feed rate and cutter rpm the "plastic planers" are using for successful cuts. i would suspect that it may be different than wood.
 

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Discussion Starter · #20 ·
i would investigate what feed rate and cutter rpm the "plastic planers" are using for successful cuts. i would suspect that it may be different than wood.
I was just thinking about that too, I'll get some larger chain sprockets to reduce the infeed and outfeed roller speeds, might get a cleaner cut that way.
Thanks!
 
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