Well, I have had my shark HD for about three weeks now and have had a lot of problems with it. Almost all of the difficulty can be related to the fact that many of the screws that are vital to correct operation were loose and not just a little bit but as much as four turns to tighten. The X axis nut was loose giving steps on the side walls of any V carving that was done. The bottom guide rod support on the X axis has three screws that hold it in place were all loose by up to four turns. It has resulted in a lost work piece that cannot be replaced and a ton of frustration for me. The user support, while there, has not been stellar and I am not sure that I will keep this machine. I like to buy American but this has been a bad experience so far and has turned out to be what I consider a DIY kit that cost a ton of money for what you get. Buyer beware.
kruizer
New Shark Pro HD
Moderators: al wolford, sbk, Bob, Kayvon
Re: New Shark Pro HD
Thanks for the heads up, Kruizer, several others have complained about the same thing.kruizer wrote:
... Almost all of the difficulty can be related to the fact that many of the screws that are vital to correct operation were loose and not just a little bit but as much as four turns to tighten.
... Buyer beware.
I intend to go over my machine thoroughly before using it.
John
Re: New Shark Pro HD
So it's not just me, they really do have a problem with this machine.Joraft wrote:Thanks for the heads up, Kruizer, several others have complained about the same thing.kruizer wrote:
... Almost all of the difficulty can be related to the fact that many of the screws that are vital to correct operation were loose and not just a little bit but as much as four turns to tighten.
... Buyer beware.
I intend to go over my machine thoroughly before using it.
kruizer
Re: New Shark Pro HD
Or, at least a problem with tightening some of the screws.kruizer wrote:
So it's not just me, they really do have a problem with this machine.
Do a search on "loose screws".
John
Re: New Shark Pro HD
For all of you folks out there that have the new Shark HD, you will want to check the lead screw nuts on all three axis and the screws that hold the support rails under the guide rods. This means you will have to remove the table from the machine to check the Y axis nut. I have been cautioned not to over tighten the lead screw nuts as they can crack if the screws that hold them in are too tight. I have found that none of the above mentioned screws were tight enough to prevent an error in something that you really want a nice job on and I lost an irreplaceable work piece because of the problem. I am still not convinced that this machine will produce an acceptable finish with anything more than really low feed rates as the head jumps around at high feed rates like it has St Vitus dance. Checked my collets and cutters and everything there has .0005 run out or less. I am at a loss to figure this out and so far not getting a lot of feedback from support. Go figure.
kruizer
kruizer
Re: New Shark Pro HD
So post your project and ask for feedback. You say really low feed rates and high feed rates. Hard to give you feedback with no project, or no cutter type/size/depth of cut/stepover/etc., what kind of wood/material you're cutting into, and your notion of low feed rate and what feed rate your found the jumping like St Vitus dance.
Re: New Shark Pro HD
I am talking about feed rates at the high end of 100 ipm and the low end of 25 ipm. The material does not matter as it can be doing a contouring move, cutting air and the head will jump at anything over 50 ipm.
Re: New Shark Pro HD
Just wondering out loud if it might be an issue with acceleration rates being set too high.
I don't use the NCpod , so I do not know if that is user adjustable or factory set. In Mach3 it is user adjustable.
Basically, if the ramp up time is too short, at high speeds the changes in speed become too harsh.
Like popping the clutch or jamming on the brakes in a car.
On my machine, if I have acceleration rates too high, direction changes can get to be like hammer blows, pounding away at the machine.
The weak links are the motor couplers and the screws that hold the leadscrew nut onto the plastic body. I have noticed others having issues with the coupler screws, which take the force of speed changes pretty directly. You may want to recheck the leadscrew nuts from time to time if you suspect they might be loosening up due to the vibration.
It's not so much the eventual speed, but how long the machine takes to get there.
If acceleration rate is user adjustable, you might want to back it down a little. (longer acceleration and deceleration ramps) That way if you were asking the machine to do 100 ipm back and forth for an 1/8 th inch of travel, it may never reach over 40 ipm as it was ramping up and then down. Then on longer stretches it would reach full speed until it needed to ramp down again.
Just a thought, but it could explain some of the things you were seeing.
I don't use the NCpod , so I do not know if that is user adjustable or factory set. In Mach3 it is user adjustable.
Basically, if the ramp up time is too short, at high speeds the changes in speed become too harsh.
Like popping the clutch or jamming on the brakes in a car.
On my machine, if I have acceleration rates too high, direction changes can get to be like hammer blows, pounding away at the machine.
The weak links are the motor couplers and the screws that hold the leadscrew nut onto the plastic body. I have noticed others having issues with the coupler screws, which take the force of speed changes pretty directly. You may want to recheck the leadscrew nuts from time to time if you suspect they might be loosening up due to the vibration.
It's not so much the eventual speed, but how long the machine takes to get there.
If acceleration rate is user adjustable, you might want to back it down a little. (longer acceleration and deceleration ramps) That way if you were asking the machine to do 100 ipm back and forth for an 1/8 th inch of travel, it may never reach over 40 ipm as it was ramping up and then down. Then on longer stretches it would reach full speed until it needed to ramp down again.
Just a thought, but it could explain some of the things you were seeing.
Re: New Shark Pro HD
What you say make a lot of sense. I do not have Mach3 and I am not aware of any acceleration comp in the VCarve system. It may be something that can be addressed by the folks at Next Wave. It sure would be nice to have a smooth contour cut at 100 ipm. It would save tons of time.
kruizer
kruizer
Re: New Shark Pro HD
Until you post a project, and / or a screen grab of your tool database settings for one of these toolpaths, it will be hard to provide any insight or ideas. This is regardless of the CNC machine or controller you are using. And it may not have anything to do with your tool selection and setup, but some condition in your project as well.
There are of course other factors that can result in this kind of erratic behavior, which at face value may seem like solely a machine weakness. One example - we have seen on this forum for example and simple square that is being used to define a pocket that had several hundred vertices, and with a g code setting in the tap file that was telling the CNC to go exactly to every point. This resulted in quite a bit of jerkiness. It was easy to make the change to the project in this case (it started out as an imported jpg). But in this case it had nothing to do with the Shark's capabilities, or tool settings in play.
For what it's worth, I have a ProPlus, and spend most of my time carving in softer woods. I am able to successfully use feed rates in the 60-70 range for pockets (cypress/pine/poplar), but again, it is not just about feed rates. For my 3D work, I was recently able to use 55 ipm on an 8% stepover 0.125 in BN cutter on black walnut. I may have been able to go higher, but that's all the time I had to get a good enough for me in the time I had to get this out the door. Of course for some areas of this project's 3D part, the machine wasn't moving at 55 due to the nature of the carving.
There are certainly times where I can't do something, or something turns out poorly, and in the end it is because I've exceeded the limits of this tool. But one thing I've learned about CNC work - there are a lot of different inputs to the outcome. Almost always, 2 or more different inputs can lead to the same outcome while carving. So, I've had to learn what all of the different inputs are that may be associated with any given condition - as looking at the one I know about now may appear to be fine, and yet I still have the condition (and need to learn the 'other' possible inputs).
If you want the maximum opportunity for input from some really sharp guys who participate in this forum, I'd post your project. If nothing else, almost always someone finds the time to run the tap file on their setup and can either confirm or deny the same outcome you are experiencing. If they are not experiencing the same outcome - for example you get jerkiness while air cutting at over 50 ipm - and they think the project is sound, then more input when you discuss this with NWA support.
There are of course other factors that can result in this kind of erratic behavior, which at face value may seem like solely a machine weakness. One example - we have seen on this forum for example and simple square that is being used to define a pocket that had several hundred vertices, and with a g code setting in the tap file that was telling the CNC to go exactly to every point. This resulted in quite a bit of jerkiness. It was easy to make the change to the project in this case (it started out as an imported jpg). But in this case it had nothing to do with the Shark's capabilities, or tool settings in play.
For what it's worth, I have a ProPlus, and spend most of my time carving in softer woods. I am able to successfully use feed rates in the 60-70 range for pockets (cypress/pine/poplar), but again, it is not just about feed rates. For my 3D work, I was recently able to use 55 ipm on an 8% stepover 0.125 in BN cutter on black walnut. I may have been able to go higher, but that's all the time I had to get a good enough for me in the time I had to get this out the door. Of course for some areas of this project's 3D part, the machine wasn't moving at 55 due to the nature of the carving.
There are certainly times where I can't do something, or something turns out poorly, and in the end it is because I've exceeded the limits of this tool. But one thing I've learned about CNC work - there are a lot of different inputs to the outcome. Almost always, 2 or more different inputs can lead to the same outcome while carving. So, I've had to learn what all of the different inputs are that may be associated with any given condition - as looking at the one I know about now may appear to be fine, and yet I still have the condition (and need to learn the 'other' possible inputs).
If you want the maximum opportunity for input from some really sharp guys who participate in this forum, I'd post your project. If nothing else, almost always someone finds the time to run the tap file on their setup and can either confirm or deny the same outcome you are experiencing. If they are not experiencing the same outcome - for example you get jerkiness while air cutting at over 50 ipm - and they think the project is sound, then more input when you discuss this with NWA support.