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Good quality (smooth) UHMW cut on PM66 table saw with power feeder

I would be very interested in the material spec for that sheet. For sure not the natural color and it appears to be a filled plastic to boot. Could be the filler causing some of the results, good and bad.
Exactly what adhesives do you use?
I have been at the manufacturing plant and they use a powder mixed with pigment which is then extruded.

Here is a TDS https://crownplastics.com/wp-content/uploads/2016/02/DuraSurfSW2001.pdf

I gotta ask - have you contacted any of the suppliers or manufacturers of UHMW for their input?

There's gotta be a way to get a clean cut without emulating a bogged down Grizzly. Or maybe not...

Good idea. When asking about one of their other machine tools (custom made CNC machine) they were un willing to share proprietary information about the machine and tooling. Maybe a table saw will be different since it is a little more off the shelf. I called and emailed their production manager about their blades, I am awaiting his response.

try using a 7" blade made for plastic, just drill the center hole to fit the saw arbor or try to order it with the right arbor hole to start with. That will reduce the surface speed by about 30%.

No Melt Saw Blades for Plastic Sheets and Extrusions -

dee
;-D

I think your on to something here. I will probably even be able to find one with a 5/8" arbor that will go right onto the PM66.

I plan to pick up a 30-40 tooth blade today with a negative hook angle, probably in the 7-1/4" diameter. Our saw vendor is looking into options for me. When I estimate the slower RPM of the Grizzly I then solved for chip load and used a chip load formula to solve for number of teeth and it put me at about 36 teeth to get the same "chip" as we got on the Grizzly.

Judging by the saw pattern on the part shown, it does not appear that the fence is parallel to the blade.

Another thought along the lines someone else mentioned: maybe the old grizzly arbor wobbled more than the PM66, possibly yielding a wider kerf that did not bind on the exit? Can you try a set of wobble collars? Not sure where to get them these days, but i have a couple old sets. Or, as an experiment, put a piece of electric tape across the bottom of one collar, and across the "top" of another before clamping the sawblade between, and see what happens.

I agree with dcsipo about the saw blade, shouldn't even need bored - aren't PM66's only a 5/8" arbor?

smt

Maybe the Grizzly did have more wobble. After the saw was about a year old the cut quality became much more consistent, maybe that was the arbor breaking down and beginning to wobble a little. No way to check it now.

Interesting idea about the wobble collars. Never heard of them and a quick google search didnt bring anything up, but I see the concept and will try it today with some tape.

Scruffy always gives good advice, but I have to comment in case the OP is not familiar with cutting edge degradation.

In "soft" substrates including wood, the bulk of blade deterioration is due to chemical erosion of the edge, which leads to blunting, leading to heat, leading to faster chemical erosion. Due to the mechanics of cutting, abrasives in un-contaminated lumber (or plastics) are usually among the minor factors.

It may be that for many plastics there is a practical feed/speed at which the substrate has little chemical interaction with the tip material. But the lack of abrasive does not automatically rule out edge wear, in some cases even "rapid" edge wear. The famous example of this is that in the first couple decades after carbides started to become common in industry, they could be used on hardwoods, but not economically with pine. The chemical reaction at cutting tip temperatures with the resin in the pine caused quick dulling and failure - faster than HSS dulled in the same material.

smt

Interesting. It seems as though UHMW is hard on our carbide cutters, but we also run at a pretty unconventional feed to heat the material and get the texture we like.
 
Judging by the saw pattern on the part shown, it does not appear that the fence is parallel to the blade.

Another thought along the lines someone else mentioned: maybe the old grizzly arbor wobbled more than the PM66, possibly yielding a wider kerf that did not bind on the exit? Can you try a set of wobble collars? Not sure where to get them these days, but i have a couple old sets. Or, as an experiment, put a piece of electric tape across the bottom of one collar, and across the "top" of another before clamping the sawblade between, and see what happens.

I agree with dcsipo about the saw blade, shouldn't even need bored - aren't PM66's only a 5/8" arbor?

smt

i think it is a 5/8" but just in case....The Forrest blades have always been the best i would buy, but pricey.


dee
;-D
 
Scruffy always gives good advice, but I have to comment in case the OP is not familiar with cutting edge degradation.

In "soft" substrates including wood, the bulk of blade deterioration is due to chemical erosion of the edge, which leads to blunting, leading to heat, leading to faster chemical erosion. Due to the mechanics of cutting, abrasives in un-contaminated lumber (or plastics) are usually among the minor factors.

It may be that for many plastics there is a practical feed/speed at which the substrate has little chemical interaction with the tip material. But the lack of abrasive does not automatically rule out edge wear, in some cases even "rapid" edge wear. The famous example of this is that in the first couple decades after carbides started to become common in industry, they could be used on hardwoods, but not economically with pine. The chemical reaction at cutting tip temperatures with the resin in the pine caused quick dulling and failure - faster than HSS dulled in the same material.

smt

Stephen
Natural UHMW has nothing to cause this chemical breakdown, that is one of its best strengths. Read on, he is using a filled plastic. Filled plastic is a completely different animal. My first tip was the pic, second tip was that they could easily sand it. 3rd was the finish with the blade backwards. It is the filler that allows these things to happen because it alters the composition of the material, possibly making it much easier to glue together. The filler makes the chips break apart and prob also prevents the blade from welding itself into a mess with the stock despite the power feeder. It is the filler that dulls the blades. I am willing to bet a proper alignment and a decent blade will solve the problem. And the fence must have a solid grip at front and back of the table so the feeder cannot push it out. You won't find these blades at Home Desperate either. Min .125 kerf on a 10" blade.
OP, what is the filler? Ask if it is ATH.
 
My "go to" blade for this would be from FS tool. I would use an XL4000 series blade for solid surface. I ran these in solid surface production in 12, 14, and 18" sizes for years and years. They also can cut super clean top and bottom on double face laminated panels. With these blades we would seam sheets together right from the saw, skipping the pass with a router to clean up the edge.
FS Tool makes them down to 8" dia.
 
OK, a few key things to follow up.

  • Our saw is now within .006in blade to fence parallelism, quality is minimally improved when feeding forward. However, our saw was out of alignment. I could not align by loosening the 3 table bolts and moving it so I pulled the table top and reset the trunions. 3 of the 4 trunion bolts were loose and the whole assembly shifted when I loosened the final bolt. I added lock washers on the 2nd side of the bolt so hopefully these don't get loose again. When this machine was aligned after we brought it in I didnt touch these bolts other than to just check that they were tight. I was also able to get align our machine only by moving the table top. This is a statement to how the material stresses out the machine. I also replaced the 3 table top bolts with allen cap screws so that we can tweak the table alignment without pulling the fence rails and outfeed table. I got the saw adjusted to within .15mm (.006in) of parallelism from front to back of blade on the fence. I plan to start making small tweaks to the parallelism.
  • Improvised a "wobble blade" with 5 strands of electrical tape "collar shims". This did not help. Maybe 5 strands was to much but I dont think this is the direction to find a solution.
  • I found out what blade our UHMW manufacturer is using. It is very similar to the blade we are using now. I am going to ask them some more questions about their setup, see if they will disclose any feed info, arbor RPM, etc....
  • I tried 2 different blades based on my idea of matching the chip load we got on the Grizzly (based on an estimated arbor RPM) by changing tooth count. In our case we needed to have 36 teeth to match the chip load of the 80 tooth blade on the Grizzly. I tried FS Tool LH743, 7-1/4"x.100" 40 tooth blade with a triple chip grind. I also tried an unknown, unlabeled blade 10"x.100" 24 carbide teeth with the same grind on all teeth. Neither blade produced a satisfactory cut. Both have a negative hook.
  • Interesting about the UHMW fillers. I don't know a lot about UHMW or plastic manufacturing but I am always learning more. I wonder if our UHMW is filled with ATH
  • We have a very solid fence setup. In addition to locking out on the front of the saw we have a t track mounted on outfeed with bolt going through the fence to keep the fence ridgid.
 
OK, a few key things to follow up.

  • Our saw is now within .006in blade to fence parallelism, quality is minimally improved when feeding forward. However, our saw was out of alignment. I could not align by loosening the 3 table bolts and moving it so I pulled the table top and reset the trunions. 3 of the 4 trunion bolts were loose and the whole assembly shifted when I loosened the final bolt. I added lock washers on the 2nd side of the bolt so hopefully these don't get loose again. When this machine was aligned after we brought it in I didnt touch these bolts other than to just check that they were tight. I was also able to get align our machine only by moving the table top. This is a statement to how the material stresses out the machine. I also replaced the 3 table top bolts with allen cap screws so that we can tweak the table alignment without pulling the fence rails and outfeed table. I got the saw adjusted to within .15mm (.006in) of parallelism from front to back of blade on the fence. I plan to start making small tweaks to the parallelism.
  • Improvised a "wobble blade" with 5 strands of electrical tape "collar shims". This did not help. Maybe 5 strands was to much but I dont think this is the direction to find a solution.
  • I found out what blade our UHMW manufacturer is using. It is very similar to the blade we are using now. I am going to ask them some more questions about their setup, see if they will disclose any feed info, arbor RPM, etc....
  • I tried 2 different blades based on my idea of matching the chip load we got on the Grizzly (based on an estimated arbor RPM) by changing tooth count. In our case we needed to have 36 teeth to match the chip load of the 80 tooth blade on the Grizzly. I tried FS Tool LH743, 7-1/4"x.100" 40 tooth blade with a triple chip grind. I also tried an unknown, unlabeled blade 10"x.100" 24 carbide teeth with the same grind on all teeth. Neither blade produced a satisfactory cut. Both have a negative hook.
  • Interesting about the UHMW fillers. I don't know a lot about UHMW or plastic manufacturing but I am always learning more. I wonder if our UHMW is filled with ATH
  • We have a very solid fence setup. In addition to locking out on the front of the saw we have a t track mounted on outfeed with bolt going through the fence to keep the fence ridgid.

uhm...did some searching and reading. When milling UHMW it is recommended to be somewhere between 600 to 1800 sfpm with a chip load of .01" per flute. So lets assume you have a 10" blade at 4000 rpm that is like 10,466 sfpm like 10 times as fast you would want....to get the chip load per flute...assuming a 40 tooth blade you need to feed it really fast. each tooth removes 0.01 that is .4" per rev and you have 4000 per minute that is like 133 feet/min? crazy fast. try to set your feeder as fast as it will go. Use a smaller blade that will let you feed at least 30% slower. I think you are melting it. Also maybe fewer teeth? Like a 24 tooth blade? I do not know if you can get a TCG with that few teeth.

good luck

dee
;-D
 
If Dee is correct, sounds like a VFD would be the cheapest next experiment? Dial in a speed that works best, then figure out the pulleys to attain it. At slow speeds with VFD the HP will be considerably reduced meaning the ability to feed adequately fast will drop off.

I would assume that a "perfect" blade with no run-out at operational rpm, and "perfectly" aligned to the fence would give best results, but had to suggest the tape/wobble just in case the old Grizzly was somehow making a virtue out of a defect. Thanks for the report. :)

smt
 
Might be time to try that fiber-cement cutting blade I mentioned. The skilsaw one I have is 6.5" or 7", but only 6 teeth. As in six. Carbide-tipped, I believe, and low rake.

Chip
 
Once you add fillers to the UHMW it becomes a very different product. Much stiffer and if it is filled with ATH then a lot more abrasive. ATH is a common filler.
 
uhm...did some searching and reading. When milling UHMW it is recommended to be somewhere between 600 to 1800 sfpm with a chip load of .01" per flute. So lets assume you have a 10" blade at 4000 rpm that is like 10,466 sfpm like 10 times as fast you would want....to get the chip load per flute...assuming a 40 tooth blade you need to feed it really fast. each tooth removes 0.01 that is .4" per rev and you have 4000 per minute that is like 133 feet/min? crazy fast. try to set your feeder as fast as it will go. Use a smaller blade that will let you feed at least 30% slower. I think you are melting it. Also maybe fewer teeth? Like a 24 tooth blade? I do not know if you can get a TCG with that few teeth.

good luck

dee
;-D

  • I have tried the power feeder at the fastest speed, but only with our 80 tooth blade. That is something to try again with some of our new blades I mentioned. This will also give a heavier chip and be less likely to melt or heat the material.
  • You could be correct about currently melting the material. I suspect the opposite. I think the cut quality we want is slightly melted. The rough looking cut appears un melted to me. Based on other tools - with our planer we feed the material about 100mm/min to get an incredibly small "chip" and in effect "melt the material". This texture appears basically the same as the backwards saw cut material. When feeding the planer faster and actually getting a decent chip and smooth cut quality the material actually shows tool marks from the planer head and has the gloss appearance like the saw cut we are getting now. I think that unfortunately our solution is to melt the material.
  • The 40 tooth blade I mentioned is 7-1/4" with TCG, the 24 tooth blade is 10" and does not have TCG. The saw vendor will re-grind TCG onto that blade if we want. I will test these 2 blades in their current state with our power feeder on the fastest speed to try that theory.


If Dee is correct, sounds like a VFD would be the cheapest next experiment? Dial in a speed that works best, then figure out the pulleys to attain it. At slow speeds with VFD the HP will be considerably reduced meaning the ability to feed adequately fast will drop off.

I would assume that a "perfect" blade with no run-out at operational rpm, and "perfectly" aligned to the fence would give best results, but had to suggest the tape/wobble just in case the old Grizzly was somehow making a virtue out of a defect. Thanks for the report. :)

smt

I agree, a VFD is the next easiest way to turn the speed down. Unfortunately being that our motor is 3HP single phase we don't have a lot of room to turn down (The Grizzly was 2HP) maybe a slight slow down would help though.

Glad we tried the "blade wobble" I like to rule out all possibilities before spending more money. It is throwing mud but the backwards blade has worked great.

Might be time to try that fiber-cement cutting blade I mentioned. The skilsaw one I have is 6.5" or 7", but only 6 teeth. As in six. Carbide-tipped, I believe, and low rake.

Chip

I did a little shopping for these and once I experiment more with the 24 tooth blade I will have a better idea if the cost of the blade is worth the test yet. Most of the ones I was looking at were starting around $70. That is about 1/3-1/2 the cost of a VFD. Ideally I would not spend money getting this saw working but realistically it will cost some money.

Once you add fillers to the UHMW it becomes a very different product. Much stiffer and if it is filled with ATH then a lot more abrasive. ATH is a common filler.

How can one become more informed and educated on UHMW manufacturing/producing? It is hard to digest the information I find in a google search. Over the past several days I have become more informed and educated on solid surfaces and UHMW but it is always nice to know more.
 
When you first started this thread, you said UHMW, so I took that as natural virgin UHMW which is what my questions and answers were based on. I have cut alot of that. I honestly don't recall cutting any with fillers. At least if I did it was not called UHMW. I agree with scruffy and once seeing your pics, I too think you have something with some sort of filler. It is out of my experience what to so with it.

I am still unsure of what surface finish you want, it seems very subjective what you are looking for. It sounds like you want a rubbed and melted finish that happens to be 'smooth'. I can produce a very nice clean smooth finish on my cnc router that does not have any mill marks whatsoever, in natural virgin UHMW it will be almost shiney and can reflect light, is this what you want?

I suggest talking to your supplier, they should be able to tell you exactly what it is or bump you up the chain to someone who can. If you are unsure of what you have, why do you have it specifically? Was this something you asked the supplier for or was it given to you by a customer or spec'd out by the customer?
 
I have a couple of UHMW pieces to machine on my router this weekend. I typically get a nice finish on the areas that I edge mill, not so much on the areas I face mill. I would love to hear how to get that clean smooth finish on the areas that I have to face mill?
 
Patternmaker - for face milling, I have had good luck with an old school flycutter, one of those that holds a lathe tool with a largeish radius ground on, 3/16 - 1/4" radius. This doesn't do you any good on a pocket where you need to get in to a corner though. If you need a sharper corner, try a small bullnose end mill, one with the corners just knocked off, that may help.
 
Thanks Macgyver. I have a some bullnose end mills but not a flycutter, do they have to be small ? Do you find lower rpm helps? I have 2 pieces the have are 6" wide by 7' long. I need to lower the whole face by 5/32" except for a 1" wide strip which gets a bunch of holes bored in it. I do need a sharp inside corner at the bottom so I will have to come back with another cutter and sharpen up the corner.
 
When you first started this thread, you said UHMW, so I took that as natural virgin UHMW which is what my questions and answers were based on. I have cut alot of that. I honestly don't recall cutting any with fillers. At least if I did it was not called UHMW. I agree with scruffy and once seeing your pics, I too think you have something with some sort of filler. It is out of my experience what to so with it.

I am still unsure of what surface finish you want, it seems very subjective what you are looking for. It sounds like you want a rubbed and melted finish that happens to be 'smooth'. I can produce a very nice clean smooth finish on my cnc router that does not have any mill marks whatsoever, in natural virgin UHMW it will be almost shiney and can reflect light, is this what you want?

I suggest talking to your supplier, they should be able to tell you exactly what it is or bump you up the chain to someone who can. If you are unsure of what you have, why do you have it specifically? Was this something you asked the supplier for or was it given to you by a customer or spec'd out by the customer?

This thread has been very informative to me. We have been using this material since 2009 and I have been on the purchasing end since about 2012. In conversation with the supplier (manufacturer) and in house it has always been "UHMW" sometimes "UHMWPE" except on stuff like purchase orders where we specify their brand name for the certain product we order. I don't think any of us have ever really thought about fillers or even how their plastic was made until we visited their plant in 2014. I have been reading about fillers specifically ATH and it is very informative although a lot to digest and hard to find specific info about ATH in UHMW.

We want the "rubbed, melted look" it also is the smoothest edge we been able to produce with a saw or with our CNC router. Two things are critical to the material and that is smooth edges and surface texture. We are able to get clean finish when face milling and planing our material but then we have to sand in order to rough the surface texture. We have to find toolpaths and feeds and speeds that give us the surface finish we need. I expect sawing is similar - if we did get the "smoothest" cut that was also not melted or glossy then we would have to sand the edges. Our Grizzly was our first cabinet saw and consequently gave us results that looked like the material coming from the manufacturer. This is what we came to call "smooth" on "UHMW" as this is the only UHMW we have worked with.

We are a production shop, other than building our own infrastructure. We buy UHMW straight from the manufacturer. Up until a few years ago our manufacturer was doing all the processing that we are now doing in house. Now they are extruding the material, cutting to length, sanding one side, and sending it our way.

I agree we should talk to the manufacturer more about this material. I will try to learn more about their setup, feeds & speeds, etc....

Kirol wrote: "I did a little shopping for these (fiber cement blades)..."

Yeah, $70 is a little steep for an experiment. I was thinking more of this one:
Irwin 1572 Fibercut 7-1/4-Inch 6 Tooth Fiber Cement Saw Blade with 5/8-Inch and Diamond Knockout Arbor - Circular Saw Blades - Amazon.com
at less than $10. (Might need spindle hole doctoring to fit.)

Chip

Thanks for finding that, I will try that.

I have a couple of UHMW pieces to machine on my router this weekend. I typically get a nice finish on the areas that I edge mill, not so much on the areas I face mill. I would love to hear how to get that clean smooth finish on the areas that I have to face mill?

To get a clean face mill on our UHMW we ran a 1/2" 2 O flute solid cutter at about 300 ipm, 20% overlap, 18k RPM. The tool has to be new or very sharp. The tool we use is southeast tool spl270. For us, it gets better with the first re-grind.
 
Thanks Macgyver. I have a some bullnose end mills but not a flycutter, do they have to be small ? Do you find lower rpm helps? I have 2 pieces the have are 6" wide by 7' long. I need to lower the whole face by 5/32" except for a 1" wide strip which gets a bunch of holes bored in it. I do need a sharp inside corner at the bottom so I will have to come back with another cutter and sharpen up the corner.

No,the flycutter doesn't have to be small, I have seen one that had a huge boring bar on it that swung app 19" diameter. The one I have been using is a cheap one that has a 3" body and holds 1/2" toolsteel. I have it swinging around 4" right now. For me the off balance nature of the cutter makes me keep the rpm down low, my spindles don't really run lower than 1000 rpm, so I set it at that when I use it. I don't remember the feed.
If you want to experiment, make a large bar that holds the tool vertical and grind it so that you can get the sharp corner, I think that just like in metal, the single point cutter makes it easy to get a good finish.

I saw this used in a video, might give you some ideas: https://www.subtool.com/st/fcs_fly_cutter_sets.html
 
Thanks Macgyver. I have a some bullnose end mills but not a flycutter, do they have to be small ? Do you find lower rpm helps? I have 2 pieces the have are 6" wide by 7' long. I need to lower the whole face by 5/32" except for a 1" wide strip which gets a bunch of holes bored in it. I do need a sharp inside corner at the bottom so I will have to come back with another cutter and sharpen up the corner.

Face milling requires razor sharp cutters. I use an Onsrud carbide chip spoil board cutter, 2.5" or 3", I forget. On my mill I run 8000 rpm, machine max. On the router I run much faster. I machine a lot of HDPE daily, enough to fill 2 gaylords a week with swarf. Virgin UHMW is sim to HDPE, chips do not want to break. That is why these plastics are sometimes used a hinges, just bending a section. The filled UHMW is a very different product. Think concrete vs Portland cement.
 








 
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