Help with broken cutting bits

[PlateCarver]

I need some advise on how to save my cutting bits. I now have about 75 hours on my machine and last week while cutting out the outline of a sign the bit broke. Thinking it was just one of those things I ordered 2 more, just in case, and yesterday went to recarve the sign. Well again on a new bit it broke again. Nothing special about this sign and it was cutting a straight piece of the outside border. The wood is Poplar so not a real dense wood.

I did upgrade designer to 1.132 just before the first one broke. I did go into designer and adjust the depth of the cut to .1 and have not had any issues....yet. I guess the question is if there is any changes in 1.132 that move the bit faster thus putting more stress on the bit? Any ideas on how I can try to prevent this?

[cnsranch]

Just make sure you're taking two or three passes to perform the cut-out.

Do not do it in one - you may not break a bit in one pass, but then again, you may...

[jcorder]

Make sure there are tabs in your cut path so the wood does not shift and pinch the bit. Been there, done that...ouch.

Good luck
Jeff

[mtylerfl]

I need some advise on how to save my cutting bits. I now have about 75 hours on my machine and last week while cutting out the outline of a sign the bit broke. Thinking it was just one of those things I ordered 2 more, just in case, and yesterday went to recarve the sign. Well again on a new bit it broke again. Nothing special about this sign and it was cutting a straight piece of the outside border. The wood is Poplar so not a real dense wood.

I did upgrade designer to 1.132 just before the first one broke. I did go into designer and adjust the depth of the cut to .1 and have not had any issues....yet. I guess the question is if there is any changes in 1.132 that move the bit faster thus putting more stress on the bit? Any ideas on how I can try to prevent this?

Hello PlateCarver,

Are you able to post the mpc so we can take a look at it? (don't post it if there are commercial patterns on it). Just curious if you are certain you are using the automatic cut path feature.

It is very strange that you are breaking bits like that - not at all normal, even with 3/4" full-depth cutouts (I do full-depth cutouts all the time, no problem whatsoever, so I personally don't believe that's the cause).

Another thing to check is that your adaptor setscrews are tight, and that the bit is fully seated before the cutout starts (brush/clean the QC before inserting the bit, then use a mirror to make sure the two red marks touch each other). Definitely could break bits if there is any trace of "looseness" in the adaptor or the QC.

Breaking bits can get expensive - fast, so please let us know if you need more assistance/suggestions to determine the actual root of the problem.

[PlateCarver]

Appreciate all of the help. The MPC was straight from the pattern area on this board that was a simple house sign. Very simple and has worked many times before for me. Strange that when I upgraded designer I stated breaking the bits. I attahed the MPC...I hope (first time) and removed the address to simplify. I did select cut board to size but it never got that far. Bit broke as it was going from the straight abd about half way up the rounded top section.

[BBrooks]

Appreciate all of the help. The MPC was straight from the pattern area on this board that was a simple house sign. Very simple and has worked many times before for me. Strange that when I upgraded designer I stated breaking the bits. I attahed the MPC...I hope (first time) and removed the address to simplify. I did select cut board to size but it never got that far. Bit broke as it was going from the straight abd about half way up the rounded top section.

When I right clicked on your cutpath and clicked on select bit, no bit was chosen. At this point you can select the 1/8 cutting bit and then max depth per pass, say .25 and it will make the cut out in 3 passes. You can also choose how many tabs per foot to use when you create a cut path. This was changed from the previous designer version when it placed tabs automagically.

[Jeff_Birt]

You DO NOT use 'Select Bit' for a Cut-Path operation. When you use the cut-path tool it will bring up it's own dialog where you can choose from the two cut-path bits: 1/8" or 1/16" straight cutting bits. You can also set the max cut depth per pass there.

[PlateCarver]

Any guidance on the number of "tabs" or is the default of 3 doable?

[Jeff_Birt]

If your doing some nested or very intricate cut-paths it would be good to use more tabs to prevent the part from breaking loose. The software now tries to detect nested cut-path operations but I would rather have to cut out a few extra tabs to free the part from the board then to have it come loose in the machine.

[mtylerfl]

You DO NOT use 'Select Bit' for a Cut-Path operation. When you use the cut-path tool it will bring up it's own dialog where you can choose from the two cut-path bits: 1/8" or 1/16" straight cutting bits. You can also set the max cut depth per pass there.

Hi Jeff,

Perhaps that was what Bill meant - i.e., choose between the 1/8" or 1/16" cutting bits in the new Cut-Out Control menu.

(Of course, if he is using the Select Bit tool during a cut path setup, that is definitely a mistake as you mentioned!)

Bill - could we get some clarification as to what you meant? Just want to make sure you're on the right track. Thanks!

[Jeff_Birt]

Thanks Michael. I was typing a quick response as I was limited on time. I just didn't want someone to get confused between using 'Select-Bit' and 'Cut-Path'. Didn't you cover this very subject in one if the Tips&Tricks?

[mtylerfl]

Thanks Michael. I was typing a quick response as I was limited on time. I just didn't want someone to get confused between using 'Select-Bit' and 'Cut-Path'. Didn't you cover this very subject in one if the Tips&Tricks?

Yes - I think it was first mentioned in the Dec '07 issue, if I recall.

[liquidguitars]

question is if there is any changes in 1.132 that move the bit faster thus putting more stress on the bit? Any ideas on how I can try to prevent this?

This is a good question and more to the point..

LG

[mtylerfl]

This is a good question and more to the point..

LG

Yes indeed. I wonder if Tech Support could shed any light on that. I'm not aware of, or noticed, any speed change during cutout procedures as compared to previous versions. Seems to work like it always has.

[dvel56]

I have the same issue with the bits breaking. They break in the same spot in the same wood 3 times and it is always against the grain on the curve of an oval sign after the tab when the bit is being lowered into the work piece. I think the feed rate is messed up I have talked with Support and sent in my patterns for evaluation and I get the same answer " nothing wrong with the pattern"
must be a loose bit or how I am inserting the cutting bit. my opion is that this is just an excuss and all the input on the forums are just a guess as to why this is happening.

[mtylerfl]

I have the same issue with the bits breaking. They break in the same spot in the same wood 3 times and it is always against the grain on the curve of an oval sign after the tab when the bit is being lowered into the work piece. I think the feed rate is messed up I have talked with Support and sent in my patterns for evaluation and I get the same answer " nothing wrong with the pattern"
must be a loose bit or how I am inserting the cutting bit. my opion is that this is just an excuss and all the input on the forums are just a guess as to why this is happening.

Try setting your cutpath max depth to incremental depths (maybe 1/4" or 3/8") to see if that helps you prevent the bit breakage.

Please let us know how you make out.

[Bubbabear]

If I am following this right this is when you have gone to the CW put the card in and setting what pattern you want it ask if you would like for it to cut out the pattern.

When you turn the machine on it gets to project menu press 0,5,6,1 then you can use the up and down arrow key and it gives you four options for cut depth. you have Full depth .375, .250, .125 .. Now this is only in the latest software 1.132. Hopefully this helps

[mtylerfl]

If I am following this right this is when you have gone to the CW put the card in and setting what pattern you want it ask if you would like for it to cut out the pattern.

When you turn the machine on it gets to project menu press 0,5,6,1 then you can use the up and down arrow key and it gives you four options for cut depth. you have Full depth .375, .250, .125 .. Now this is only in the latest software 1.132. Hopefully this helps

No, Bubbabear. What we're talking about is using the Cut Out Control Menu within Designer. Offers complete control over individual cut paths. That feature was added in version 1.131 and "changed the world" of how CarveWright User's can have control over their cut paths like never before.

Please read the ISSUE 12 September 2008 – Designer 1.131 New Feature Highlights (http://www.carvewright.com/downloads/tips/CarveWrightTips&Tricks_Sept08.pdf) for details on how this works.

[Bubbabear]

Sorry Michael that is what ever one thought I was talking about when I had the problem I was having. But it was the one that is fixed with 1.132 so I thought I would mention it

[mtylerfl]

Sorry Michael that is what ever one thought I was talking about when I had the problem I was having. But it was the one that is fixed with 1.132 so I thought I would mention it

Oh - - yes. You're talking about the "cut board to size" at the machine. My apologies! That's a completely different function. Sorry if I added to anyone's confusion!

[BBrooks]

Hi Jeff,

Perhaps that was what Bill meant - i.e., choose between the 1/8" or 1/16" cutting bits in the new Cut-Out Control menu.

(Of course, if he is using the Select Bit tool during a cut path setup, that is definitely a mistake as you mentioned!)

Bill - could we get some clarification as to what you meant? Just want to make sure you're on the right track. Thanks!


um,oops, uh, yup...I did mean to say the cutpath dialog, not the bit selection dialog. Right idea, wrong presentation. Sorry for the cornfusion.

[mtylerfl]

um,oops, uh, yup...I did mean to say the cutpath dialog, not the bit selection dialog. Right idea, wrong presentation. Sorry for the cornfusion.


:D Hey, we're just all confused lately! :D

[jcorder]

:D Hey, we're just all confused lately! :D

I try and stay confused, gives me an excuse to screw up!

[liquidguitars]

We know we can make a outline path from a raster image and use "cut path' so we can control the auto tabs and the depth for cutting. also "one pass" is the default setting what i like to use overall.

With 1.132 the feed rates are faster for thin cuts you can see this, but its seems just as fast for full dept cutting 2.


LG

[mtylerfl]

Hello,

For what it's worth...

I spoke with one of the "upper-classmen" in Tech Support today to get his take on why some folks are having bits break and others do not (like me).

He is convinced the most likely cause is that the QC has residue inside that prevents the bit from fully seating. I have a tendency to think that too. He mentioned another possible cause is a loose setscrew. Still another possibility is that the adaptor has BB marks and allows the bit to "flop" a little.

Most of us know that when severe BB marks are observed, it's time to change the QC and the adaptors simultaneously. However, based on Tech's experience over a wide range of users, a "dirty" QC that prevents full and complete seating for the bit is the most common reason he finds for users that experience repeated bit breakage problems. EDIT: Just wanted to add that we both assumed the user is keeping the project under the rollers at all times - I think that's a "given" for those of us who have been around awhile, but thought I better mention that just in case a new user reads this and doesn't know to keep a project under the rollers.

Often, especially after a long carve (which is practically everything I do personally), very fine powdery sawdust gets inside the QC. If the cutting bit (or whatever bit) is placed into the QC without removing this debris prior, there is a chance the bit might not be fully seated, causing runout and overstressing the bit - - creating a possible 'snap' scenerio!

I know I've said this before, but...I brush/clean the QC thoroughly between bit changes (as well as at the end of a project session, of course). Then, when I put in the next bit, I verify that the two red marks touch, and I "tug" down on the bit to make sure it's all in, good and snug. Also, I now make it a habit to check the setscrews before putting any bit/adaptor assembly into service.

Now, having said all that, Tech says sometimes by using the "old" method of multiple passes for cutpaths, you can "get away with" a bit that might not be fully seated. It might be in place just enough where the multi-pass method masks the underlying problem and keeps your bit intact and completes the cutout. The only thing you might observe is more noticable "stepping" on the cutout's edge due to the bit runout. You usually can't get away with any bit slop on a full-depth cut, says he.

The upshot at the end of my conversation with the Tech, is that he felt that it might be good for the folks that are having the breaking bit problems to go ahead and utilize the multi-pass setting for their cut paths. As described above, there is a chance that even if their QC has debris inside preventing the bit from a full-seating installation, they might not break bits as readily. He was quick to mention though, that he wished everybody kept the QC's "really clean" and possibly avoid the problem altogether, or at the very least, eliminate that as a cause to help with diagnosis for other possible things to check.

I completely forgot to ask if there was any feed rate change for cut paths in 1.132 (I'll ask the software guys next time I talk to them). I haven't noticed any cut path rate change myself, but I often start a project then monitor it from a closed-circuit audio/video security system. That may have crippled my ability to pick up any difference - especially if it is subtle, and especially if I have both machines going at the same time. In any case, the Tech was pretty adamant that the bit breakage is avoidable if the QC is kept clean and clear.

I certainly hope this is helpful.

[liquidguitars]

That may have crippled my ability to pick up any difference - especially if it is subtle, and especially if I have both machines going at the same time.

Upload a project with just a cut path in 1.131 and the same in 1.132 that will answer the question.

I agree about running "min pass" at this time until LHR reviews... it would be cool if you could just select the type of wood you are using when uploding to the firmware so faster for "clear pine" that you like to use a lot, and a bit slower for "softmaple" ect..

"speedtest.mpc" version 1.131 time 8:06 min
"speedtest.mpc" version 1.132 time 6:42 min

I running a wireless CCD from Linksys to view my carving good way to go... :) 8)

LG

[mtylerfl]

Upload a project with just a cut path in 1.131 and the same in 1.132 that will answer the question.

I agree about running "min pass" at this time until LHR reviews... it would be cool if you could just select the type of wood you are using when uploding to the firmware so faster for "clear pine" that you like to use a lot, and a bit slower for "softmaple" ect..

"speedtest.mpc" version 1.131 time 8:06 min
"speedtest.mpc" version 1.132 time 6:42 min

I running a wireless CCD from Linksys to view my carving good way to go... :) 8)

LG

Thanks, LG for the info.

What was the thickness of the board (& depth of cut) in the time comparison? Was it 3/4" ?

I spoke to Chris L. awhile back in the "early days" of the full-depth cut introduction (I think it was in Sept. of last year). He said they run 3/4" walnut, maple, oak, and pine in their shop with no issues with the full pass cut outs. At the time I was a little "skiddish" about the full-depth cuts, but have run all my projects since then at full-depth and it has spoiled me - I really like the feature. However, I have not run thick (3/4") hardwoods, so have no experience with that - just trusting the positive feedback I have received from others.

I know you run a lot of hardwoods for your wonderful guitars. Have you experienced any bit breakage problems during full-depth cut outs on thicker hardwoods with either 1.131 or 1.132?

[liquidguitars]

Just to be be clear I am not stating that the firmware has anything to do with snapping bits as it could be a number of real world probs..
like you said the QC need to be clean and the bit wiggle free, bits need to be sharp and free of dirt and glue ect..


LG

[supershingler]

just a thought on keeping the qc clean

maybe lhr could come up with a brush similar to the old post and cable cleaner that i used to clean up the battery cable on my vehicles but with a stiff but non abrasive bristles that a person could just stick up in the chuck and give it a few turne to break loose all the sawdust and debries that might be impacted in the qc.

a tooth brush work alright but a brush like this would work great and be an asset to everyone.

thanks for looking

kendall

[Jeff_Birt]

The #1 most important thing to keep in mind when using the quick chuck and adapters is to keep a rag handy to wipe then both off between bit changes. Any debris on the tapered mating surfaces will prevent the adapter from seating correctly in the chuck.

As I'm setting up the machine to do some carving I grab a new 'heavy duty' blue paper towel off the roll and put 3-4 drop of 3-in-1 oil on one corner and wipe out the chuck, then I wipe off each bit/adapter as I put them in for the initial measurement. When I switch bits I take another quick wipe of the inside of the adapter and also wipe off anything on the bit/adapter I removed. It takes hardly any time at all and prevents all sorts of problems (like broken bits and bb marks on your adapters.)

If you have any machine shop experience this business of keeping the chuck and adapters (chucks and collets) squeaky clean is old hat. If not then it might seem a bit foreign. The key points are that it is easy to do, takes almost no time and it is absolutely essential.

[ChrisAlb]

I think over oiling the QC makes it much harder to keep clean as well. On my first QC I got about 410 hours out of it and I applied a VERY small amount of 3 in 1 with a rag about once a week.

I now have almost 40 hours on my second QC and have never put any oil on it at all. I only wipe (again with a rag) a small amount on the adapters just to keep the retaining balls in the QC from rusting.

So far, I find the "dry" dust falls out MUCH easier than my previous approach. I still use a tooth brush but after snapping the QC a few times, not much more comes out with the brush. Also, it's important to brush around the set screws on the adapters. Without fail, every time I take a bit our there is a small amount of dust on the set screws right at the body of the adapter. It might not look like much but ignore this just a time or two and it WILL be enough to keep the QC from completely locking around the adapter.

Just my two sense.

[PlateCarver]

I appreciate everyones help with this. I have reset the cut path for multiple passes to avoid help with this.

Another question. While the cut path is adjustable as far as depth what about the option to cut the board to size? I do not find a setting for that and am concerned that this may be again an all at one time cut...

[ChrisAlb]

At this time there is no way to make multiple passes on a cut to size. You could use a couple straight lines and apply the cut bit to them.

Personally, I would never use the CW to do this anyway as my sliding chop-saw and table-saw are much faster for this and saves wear & tear on the CW and bits.

[Bubbabear]

At this time there is no way to make multiple passes on a cut to size. You could use a couple straight lines and apply the cut bit to them.

Personally, I would never use the CW to do this anyway as my sliding chop-saw and table-saw are much faster for this and saves wear & tear on the CW and bits.


Chris in 1.132 you can change the cut board to size when you are at the machine. Post 17 in this thread has it in detail

[ChrisAlb]

Chris in 1.132 you can change the cut board to size when you are at the machine. Post 17 in this thread has it in detail

Thanks for correcting me Bubbabear. Since I never use it, I would have never known they added that.

So I guess once you answer YES to "cut the board to size?", it gives you the option to specify how many passes?

Another added feature....Cool.

[Bubbabear]

Thanks for correcting me Bubbabear. Since I never use it, I would have never known they added that.

So I guess once you answer YES to "cut the board to size?", it gives you the option to specify how many passes?

Another added feature....Cool.

No Chris before you start the setup go 0,5,6,1 on the keypad then it stays set until you change it gives you 4 options as I listed in #17 using the up down arrow key

[liquidguitars]

I appreciate everyones help with this. I have reset the cut path for multiple passes to avoid help with this.

You can now join the "min pass" club :)

LG

[Bubbabear]

If I am following this right this is when you have gone to the CW put the card in and setting what pattern you want it ask if you would like for it to cut out the pattern.

When you turn the machine on it gets to project menu press 0,5,6,1 then you can use the up and down arrow key and it gives you four options for cut depth. you have Full depth .375, .250, .125 .. Now this is only in the latest software 1.132. Hopefully this helps

So it is closer to here and no searching

[PlateCarver]

Well after making the changes in this thread the cut paths worked perfectly but when I chose the "cut board to size" another broken bit. I am going to go back a release as after 3 bits its getting a little expensive.

[mtylerfl]

Well after making the changes in this thread the cut paths worked perfectly but when I chose the "cut board to size" another broken bit. I am going to go back a release as after 3 bits its getting a little expensive.

OK! I think we might be closer to an explanation as to why your bits are breaking. When a board is cut to size, it is not being kept captive under both rollers. I'll bet the board is tipping slightly, causing the bit to bind and therefore, the bit breaks.

Two solutions -

1) Don't use the cut board to size feature - put in a board that is already the correct size to begin with.

2) If you still want to use the cut board to size feature, then make sure the outfeed tables are adjusted perfectly to prevent the board from even slight "tipping". If your board is over say, 40", then use a couple stand-alone roller supports in addition to the built-in outfeed support to prevent tipping as well.

[Bubbabear]

Well after making the changes in this thread the cut paths worked perfectly but when I chose the "cut board to size" another broken bit. I am going to go back a release as after 3 bits its getting a little expensive.
If the 0,5,6,1 then set depth (I set mine a .125) didn't fix the broken bit. The I guess I would stop using it. But i certain cases and times I sure do like it. I would also call LHR

[PlateCarver]

I wll call LHR and see if there is anything they may suggest. The strange thing is that I have over 75 hours on the machine and the only bits I broke were after moving to the new release. No other changes and I have used both stay under rollers and not. I did notice that when it went to "cut to size" it did not go to the .125 I set in the previous threads...it did a one pass cut.

[lovejoys]

I have 1.132 and did the update

now the board moves more jurky when it does a cut out I can see how this will break more bit

1.131 moved the board more evenly at the same speed and slower

this is just what I can see doing some cuts on both

[Jeff_Birt]

Guys I have been beta testing 1.132 for a few months. I have witnessed no such jerky movements nor had any broken bits. I've used every release since 1.013 or so and have never broken a bit. I'm not saying that this release is perfect just that it seems some other mechanical issue is more likely.

Jerky board movement is most likely due to the board binding in the machine or a broken X drive gear (from a board binding in the machine.)

[lovejoys]

sorry but same machine same gears it is only jerky only on the cut outs
next idea please

[ChrisAlb]

Is it the board movemnet (X axis) or the truck movement (Y axis) ?

[lovejoys]

its the board and only on cut outs

[Jeff_Birt]

Sounds like you may have some slipping on the drive (sandpaper) belts. It might be worthwhile to check your head pressure.

In case there is something going wrong with the cut-path speed in this new release it might be a good idea to set your projects to use shallower cuts.

[Jeff_Birt]

For the folks having some problems with broken bits. Are you using the built in 'Cut-Path' tool (the icon with the little saw on it)? If so be doubly sure you are not also trying to manually assign a bit to the path with the 'Assign Bit' tool.
Please let us know either way.

[lovejoys]

it's not the belt if it was somthing else it will be seen when I do a normal carve as it move but this is ok

it is in the program

[mtylerfl]

it's not the belt if it was somthing else it will be seen when I do a normal carve as it move but this is ok

it is in the program

Hello,

Are you able to post the mpc that is giving you the trouble? (don't post it if it has any commercial patterns of course)

It's a long-shot, but thinking maybe if we could take a peek at your actual mpc, it might be helpful.

Another thing to try - go back to version 1.131 and run the exact same mpc and see if the issue is still there or "goes away".

That "jerky" movement sounds more like a belt or encoder problem (or maybe a sliver of wood was interfering with the belt, loose bearing, etc.). I have doubts it has anything to do with the 1.132 version.

[Digitalwoodshop]

Masking tape is your friend.... If the brass roller looses contact with the board the resulting jump will break the bit.....

AL

[Dyna Rider]

If the brass roller looses contact with the board the resulting jump will break the bit.....

AL

Hey Al
Read several of your posts and you seem to have a real good handle on the problems and fixes associated with this machine. I can sort of see that the momentary stopping of the roller being the cause for the board to jump. But the reason eludes me; care to explain the sequence of events? Or point me in the direction of some reading material.

Bill

[Kenm810]

"Amen" AL,

Since you first posted that Info, I've used it on all of my Project Boards and Sleds.
And I whole heartedly agree that a roll of Masking tape is far less expensive than wasting
a fine Oak, Cherry, or Walnut project board caused the Brass Board Traction Sensor slipping and Stair Stepping.

[liquidguitars]

I like the tape under the Aux roller 2 but not to much
as tape can gum up the sled if over done..

LG

[Digitalwoodshop]

Golly... Guys.... Now my head is swelling from EGO...... It's past Midnight and I have some Fire Tags in the UV oven so I have a half hour to kill while I jam to the 80's on Sirius and surf the net.


The big advantage that a Shop Bot has over our unit is that all axis drives are controlled with stepper motors and I believe feedback Encoders. The Stepper has the ability to be told to count or MOVE 5 steps and the stepper motor does 5 steps with reliability. It has a belt gear system that is closed loop so it is very accurate. Some of the cheaper versions might only have the steppers and no feedback to the computer.

Since the board is held to the table the with clamps or air suction it does not move. With all axis being very reliable in motion you would never get the stair stepping doing a cut out with a Shop Bot.

So now to the CarveWright.

It uses Servo Motors and Encoder Feedback too for the Z or Up and Down Axis and the Y or left and right axis. The X or Sand Paper Axis uses a Servo Motor and has an encoder as seen in the first 3 pictures. The 4th picture is a Encoder. Nothing more than a LED light and a photo receiver. In picture 5 you see the encoder mounted to the back of the Servo Motor so when the motor moves the plastic disk has lines on it as seen by the sun shadow. The lines block and let the light through like holding your hand over a flash light. Each line in the plastic disk is a pulse of the encoder. So now the computer tells the Servo Motor to move in a direction and say count 5 pulses and stop. Just like the Steppers of the shop Bot it will control the motion with great reliability. I believe the Servos are MORE accurate and are MORE Responsive, but I am biased as I am a Old Navy Analog Fire Control Computer Technician. My first Computer in 77 had Vacuum Tubes and lots of SERVOS and gears.

So for this example we will say that the steppers and servos are a equal and will both give you a great cut.

Now the X Axis.... In the CarveWright the HEAVY board is moved in length as the 3rd axis. This is accomplished by the Same Servo Motor used to drive the Y and Z but has the MECHANICAL ADVANTAGE of the BIG PLASTIC GEARS as seen in the pictures 1, 2, and 3.

The difference is that for any given linear X Axis motion, the servo motor is going all out.... Like peddling a bicycle in 1st gear.... Your legs are going like mad but you are going slow. The advantage is on a hill, you have the mechanical advantage of 1st gear. Same here with a heavy Board, the gears level the playing field.

Back to the CarveWright. It must move the heavy board for measuring in length and do all the FANCY small movements when Vector Cutting a letters or cutting out a Circle or Oval Cut Path.

It "could" rely on the encoder on the X Motor but because the sand paper belts move the board and the "Possibilities of SLIPPAGE", it was decided by NASA Engineers that designed this machine, to place a Brass Roller Encoder between the sand paper belts touching the board. This gave BETTER QUALITY Feedback of the board movement since it was so critical to the accuracy of the machine.

Think of everything that must go RIGHT for the machine to cut a perfect Circle in wood. Perfect movement between the X and Y to make it perfect.

You may hear from time to time on the forum about doing calibration.... What Calibration does it tell the computer that say for example the Y Axis will move 28 pulses of it's encoder for every 1/2 inch of Linear movement. Now the X has a Brass Roller and in calibration it finds that it takes 34 pulses of the Brass Roller to move the board 1/2 of a Linear inch.

Imagine if the brass roller 34 pulses were changed to 28. That could cause the machine to cut a OVAL when it wants to cut a Circle.

The Shop Bot has complete control over it's 3 axis PLUS the board never moves. This is a perfect world, and you get Quality work. I know Shop Bot has a new Stick Axis but we will ignore that for this example.

Now the mechanical part of the X Axis in our machine....

I have had a board slip on the sand paper belts.
I have had Cupped boards loose contact with the brass roller.
I have has boards with a knot missing at the brass roller area.
I have had OAK boards loose contact with the brass roller, the rubber O ring not catching the slippery board.
I have had a splinter of wood missing along he Brass Roller path.

So the X Axis is moving along doing your cutting, all of a sudden the brass roller looses contact with your board. The Computer is DUMB and knows it is looking for pulses from the brass roller and it will KEEP MOVING until it see's the correct number of pulses. If you are in the middle of a CUT PATH with the bit in the middle of the wood, and the Brass Roller loses contact the X Drive, it HAS the TORQUE and Power to SNAP the BIT......


So this is why I say..... It's ALL ABOUT THE BRASS ROLLER.... It is the WEAK LINK of the machine but the link that makes it a very COST EFFECTIVE MACHINE.

So it is ALL about controlling the board's contact to the brass roller. I have about a dozen samples of BAD CUTS before I understood the IMPORTANCE of the Brass Roller....

For ME Masking tape is a Insurance that the brass roller will stay in contact with the wood. You can SEE the tracks in Ken's pictures, like a gear meshing with the board. A board foot of wood will buy you a few rolls of tape. CHEAP Insurance.

I don't recommend you do this BUT...... While the machine is measuring a board and you start to release the hand crank, the board will eventually loose contact with the brass roller and start JERKING AROUND and sometimes ROCKS BACK AND FORTH. This is the machine getting POOR Brass Encoder Data..... "YOU COULD BREAK A X GEAR TRYING THIS AT HOME.. I WARNED YOU.... :)"

Hope this helps.... Sort of beat it to death...... I was a Navy Electronics Instructor for a few years so this is what I find FUN..... Sure... at 2 AM..... My Epoxy is done, I can set the timer one last time and go off to BED....

My web site has my Navy Story with pictures of the Analog Computer....

AL

[Digitalwoodshop]

The first 4 pictures are examples of the X Brass Roller loosing contact with the board.

The last picture is a comedy of errors....

1. Hard Wood.... Oak

2. A Dull Carving Bit.

3. A WORN Y Gear Box Bushing. This caused the belt to SLIP on the Y AXIS.

The Y Bearing WILL WEAR and let the belt SLACK..... This will cause Y ERRORS in carving.

REMEMBER when this happens on a WEEKEND and you want to CARVE..... Then REMEMBER AL said the OLD JUNK GEAR BOX FROM the NEW Z Bundle will WORK..... YOU can Remove the Gear Box from the OLD Z and INSTALL IT on your BAD Y.....


AL's Tech Help Fund Drive like PBS....... Snicker....

Please Send Donations to AL's Pay PAL digitalwoodshop@aol.com

Night Night....

AL

[Dyna Rider]

Hi Al

Read your post, got a couple more questions.



So the X Axis is moving along doing your cutting, all of a sudden the brass roller looses contact with your board. The Computer is DUMB and knows it is looking for pulses from the brass roller and it will KEEP MOVING until it see's the correct number of pulses
AL

So if I started the machine and removed the brass roller, the X-drive motor would continue to run? In the fifth picture from the left, the optical encoder, is that on the X-drive motor?



If you are in the middle of a CUT PATH with the bit in the middle of the wood, and the Brass Roller loses contact the X Drive, it HAS the TORQUE and Power to SNAP the BIT......
AL

As long as the bit continues to spin and cut, the machine losing its orientation may ruin the work, as in your pictures below. But why would it break the bit. In the work below did you break any bits?

Have you ever taken the Brass wheeled board tracking encoder apart, if so do you have any pictures.

Bill

[Digitalwoodshop]

[QUOTE=Dyna Rider;78163]Hi Al

Read your post, got a couple more questions.



So if I started the machine and removed the brass roller, the X-drive motor would continue to run?
I believe it would run non stop.

In the fifth picture from the left, the optical encoder, is that on the X-drive motor?
No, it is a Z Motor Encoder.



As long as the bit continues to spin and cut, the machine losing its orientation may ruin the work, as in your pictures below.
A long bit like the 1/8 would break easier but not a Carving Bit or V90.


But why would it break the bit.
Depending on how deep the bit was and how far the X jumped or moved. Again, I am betting you broke a 1/8 inch bit.

In the work below did you break any bits?
No. The Rail Road Tracks were very shallow.

Have you ever taken the Brass wheeled board tracking encoder apart, if so do you have any pictures.
No not yet.



Hope that helps.

AL

[Dyna Rider]

Hey Al
I’ll take that bet…nope haven’t broken a bit yet. But then, I only have about twenty hours on my machine with two hours on the cut motor. At present my machine is a fifteen hundred dollar paperweight and I will say it functions extremely well in that capacity.
I think what the motor will do depends on the algorithm that controls the motor. I’m still attempting to put my thoughts down, but without much success. So here are a couple fragmented thoughts.
The software knows how many steps are required for the motor to advance the board a given distance. It downloads this information to the controller. In one thought, the controller is given the number of steps the board encoder must take to advance the board the given distance. It sets a counter and counts each step of the board encoder. Once the count is reached it stops the motor. If the count is never reached the motor continues to run. In the next one the controller knows how many steps the motor must take to advance the board a given distance. It sets two counters, which count down, one for the motor and one for the board encoder. At the end of the count if both counters agree the controller fetches the next instruction, if not the motor stops and sets an error code.
Do you have any information on the Controller?

Bill