Expected Life for the CNC Shark HD4

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Brums
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Expected Life for the CNC Shark HD4

Post by Brums »

Interested in purchasing a CNC Shark but was wondering what a person should expect on the life of the machine before you need to start replacing parts with the assumption that the machine was treated correctly. Can someone comment on the history of your machine and the cost of running the machine over the years of use.
Thanks

Rando
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Re: Expected Life for the CNC Shark HD4

Post by Rando »

Brums:

TL;DR: There are really only two types of "wear parts" on the machine: the anti-backlash T-nuts, and the spindle/router motor. I'd add in the aluminum touch plate too, since it does develop very tiny cut marks over time, decreasing Z0 accuracy. If you don't crash, the T-nuts will last a good decade. The spindle and router fall under the normal MTBF distribution for motors, so there's always some finite probability that it will fail...today. My DeWalt D618 router went south pretty much the moment I started cutting deep holes in blocks of metal (after about 18 months of ownership), others who I've heard saying they replaced their routers seemed to get between 2 and 5 years, with some being able to replace the brushes and go back to working as normal. The aluminum plate is a standard thickness, and you can set the new plate's thickness, so that's not a problem either.

Like with most machines, a lot depends on how badly you beat it ;-).

Each of us experiences machine "crashes" at one point or another. Each time the machine drives the lead screws and follower anti-backlash T-nuts into some obstacle, it damages those plastic nuts. They are designed to take up some of that wear (that's why they're anti-backlash, backlash being a wear component), but eventually the slop in movement will give your circles flat top/bottom or sides, depending on which axis of movement has been abused most egregiously.

Crashes don't have to be against the ends of movement, however. Injury can occur if it gets run up against anything non-movable: a clamp, a vise, a firmly-planted piece of stock, and so on.

As a new user, the faster you get up to the necessary care in knowing how the machine will react, and thus avoid any crashes, well that will vastly increase the life of the machine.

Other things to avoid are: drilling into the bed, knocking it off the table, etc., If you're considering parting out the old shark when you're done, and reusing components, the steppers will probably do just fine, and the rails and slides would be fine. But, as discussed in a different thread on extending the bed, new mechanicals are relatively cheap compared to building it out yourself from parts.

If you upgrade to an AC brushless spindle motor (over the router), those don't have contacts, so it's really just replacing the bearings every few years when runout becomes unacceptable.

Whether the system remains compatible with "current" PC technology is another thing. Thankfully, USB isn't going anywhere. Regrettably, if a significant driver-model update was required (like they did with printers in the Windows 8 generation), it's very likely the controller would not get updated, effectively stranding that CNC to only work with old (and sooner dying) computers. Companies who depreciate and replace equipment will find that unpleasant.

So, if you treat it well, it can easily last 10 years. I've had mine for about 2.5 years, used frequently, but not daily. So far, it's held up great, with all too frequent machine crashes: I machine aluminum, and getting to where that was successful took a lot of time, ruined stock, and broken bits. Trust me, Halloween horror movies have nothing on the terror you will feel when you see the CNC pushing with all its might against a 50# Kurt machining vise that's bolted to the bed. Especially when you look up and realize it's going to continue pushing for what it thinks is another two feet :shock:

The biggest thing you can do every single day to improve your machine (and bit) lifespan is to get your feeds-and-speeds exactly right. Watch carefully how the cuts go; don't just walk away and then be confused when it comes out less than perfect. Learn how to calculate and validate those numbers, for real. Don't give ballpark numbers, keep a record of exactly what works and how well. Having a cut catalogue of known-safe cutting parameters will go a LONG way toward ensuring you don't overstress the machine during "normal" runs. And trust me, there are LOTS of places where a toolpath can make the machine's life hell, when that machine is flexy-bendy like the Sharks are. Don't get me wrong, I'll be the first to say you can get some surprisingly good work out of them. But, they're not a $15,000, or $150K, or $1.5M machine...they're a couple thousand bucks. Heck, they're so inexpensive that I've probably spent more on extended-reach and radiused endmills (and then turned around and broke them :( ) than the base machine cost ;-).

And, that's the important point: over time, if you do real machining and replace worn carbide bits for real, you will likely spend as much or more in tooling than the base machine. And the longer you use the machine, the more that bit-cost rises. So, to reduce total cost of ownership, your best place to look is in making sure your bits don't get chipped and dulled. And the biggest reason carbide bits get dull? Too much heat! Either from going too fast or too slow, too much heat kills the tempering on the carbide, and it looses it's sharp cutting edge pretty much right there. If you're doing a production run that takes four days, and you go through a bit a day because of bad toolpaths, it's better to fix that toolpath and F&S, so that bit lasts an entire month, not just a day. It's possible, and I've been doing it. And not doing that is far more expensive and frustrating :D.

And, of course, what is supposed to cost more than the bits and machine? The value of the product coming out. If THAT gets horked up through bad toolpaths, or controller movement errors, and so on, then you're paying double the raw material costs. We've seen people go through maybe a half-dozen iterations on a design using panels multiple-square-feet in size due to some stupid cutting issue that came down to...you guessed it: their F&S and cutting parameters. On any major design, I include a full day to completely validate (as in actually check) all cutting parameters in all toolpaths. And some of the parts I make have 50+ toolpaths. It's daunting, but knowing the cuts CAN succeed is huge. But again, this is much more an issue the more you're pushing the machine. Don't imagine this only happens in "hard" projects, either: managing deflection will be your constant obsession.

If you treat it well but run it hard daily, I'd guess it would be on it's last legs somewhere in the third year, with the entire system slowly loosening up and getting out-of-tolerance. So, estimate about 3-4 years total running time. The more slowly you use the time, often the more total time you'll have, since each use will be less hard on the machine.

Hope that gives a little perspective on the question.

Regards,

Thom
Last edited by Rando on Thu Nov 02, 2017 12:29 pm, edited 3 times in total.
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studio-n
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Re: Expected Life for the CNC Shark HD4

Post by studio-n »

Keep things lubricated and you'll be ok.
I think you can expect to go thru more routers than shark parts.
1st Porter Cable router lasted less than 100 hours of use.
on my 3rd.
"Out of my mind.....back in 5 minutes"
Rockler 60th Anniversary CNC Shark
w/digital probe, and 4th axis attachment.
ULS M300 Laser Engraver 50 Watt
Aspire and Corel Draw
NextEngine 2020i 3D scanner

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Kayvon
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Re: Expected Life for the CNC Shark HD4

Post by Kayvon »

Great advice so far! I'll try not to diminish it.

I've been using my original Shark for over 3 year, using it at least once a week. I haven't had to replace anything except bits so far. The handheld Bosch router is still working well.

I'll echo Thom's advice on bit speeds. I'm less careful than he is, however, but I'm also using softer wood materials, rather than harder aluminum. To that end, most of my bits are cheap chinese bits. I've purchased precision 6mm and 1/8" collets to help. Because of this, I don't mind tossing a bit when its performance drops, since they're only a couple bucks apiece. That said, I manually adjust the feed and speed with each project to achieve a better finish and less wear.

Of all the frivolous purchases I've ever made, the CNC is my absolute favorite. I've used it every day this week and I'm still finding new applications for it.

Brums
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Re: Expected Life for the CNC Shark HD4

Post by Brums »

Thanks to all for the information you provided.

4DThinker
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Re: Expected Life for the CNC Shark HD4

Post by 4DThinker »

Best thing to make routers last longer is to run them one notch slower than their maximum speed. Often the bearings used aren't design to spin continuously at the max speed that the router runs. It's also a good idea to change out the brushes before they fail completely.

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