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1 Attachment(s)
Marchant Dice router no thrust bearings?
I have been aware of the fact that there are no thrust bearings or any sort of proper ballscrew mounts on my marchant dice router. Up until now it ain't been much of an issue as I was cutting soft mdf and plastic at slow speed. Last week I had a job to cut some birch and I noticed the accuracy to a hit. All my dimensions were consitently off by 0.4mm or so, regardless of the length of the dimension, this sound like backlash. The couplers are tight so I reckon it is due to the fact that the ballscrew does not have a thrust bearing and the design realise completly on the stepper motor resisting the force on the ballscrew. The stepper won't do this as I was expecting, so I think I will prob need some proper mounts.
Has anyone else got a marchant dice A4 sized router with the same prob?
Here is a pic of the current setup. x,y and z are all indentical.
The x axis ballscrew end arrived bent and the coupler had a lot of runout in the machining, so much so that it wiggles the stepper motor a lot as the axis is moved.
Attachment 7936
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Re: Marchant Dice router no thrust bearings?
I had a bad experience trying to deal with Marchant Dice so I dont go near them anymore. Thats really poor build quality not having any support bearings in place. If the shaft is bent and directly affecting the stepper then it will eventually knacker up the stepper motor as well. If you grab the ballscrew by hand can you get any play in it by trying to move towards and away from the stepper?
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Re: Marchant Dice router no thrust bearings?
Hi Web Goblin,
Quote:
If you grab the ballscrew by hand can you get any play in it by trying to move towards and away from the stepper?
Yes lots, prob over a mm. :(
Quote:
If the shaft is bent and directly affecting the stepper then it will eventually knacker up the stepper motor as well.
I know its only a matter of time before it knackers the motor. I actually completely rebuilt the machine last week, had the ball screw in the lathe to check the runout on the ends, straighten it out as best I could. A new coupler would help matters as most of the runout is in the coupler. Actually I thought to myself Ill get some oldham couplers, then I relised I couldn't because the coupler needs to be ridged to work as the motor is holding the screw in place, pretty crap huh.
I know merchant sell multiple routers like this a week I find it stange that they don't support their ballscrews. If they did I think they would have quite a nice product
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Re: Marchant Dice router no thrust bearings?
Your right, an Oldham coupling definetly wont work. Most couplings will be able to take out some axial play but not any along tha axis. You could disconnect the stepper and see if there is any play in the shaft to see how its holding up. Looking at the photo its hard to see what you will be able to modify to add a bearing block to support the shaft. what you might have to do is make a bearing block to fit on the motor side of the vertical support and then an extension shaft to be able to refit the motor and coupling. Saying that you could save a bit of space by making the through hole for the ballscrew larger and recess the bearing block in it.
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1 Attachment(s)
Re: Marchant Dice router no thrust bearings?
Attachment 7937
If I could fit a block in the inside like this I could retain the same mounting block for the motor. I would be a little hesitant about milling into the aluminium extrusion as I don't have a mill.
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Re: Marchant Dice router no thrust bearings?
Yes that should do the trick. Didnt know if you could get it on the inside but if you have enough space that would do. Cant you mill it on your machine?
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Re: Marchant Dice router no thrust bearings?
Its shocking to see that companies selling crap like this can get away with it, i my opinion thats not even fit for its purpose. Shocking....
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Re: Marchant Dice router no thrust bearings?
is there anything on the other end of the ballscrew
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Re: Marchant Dice router no thrust bearings?
The other end is floating inside a bearing which is pressed into the gantry extrusion. I thought about welding a new end onto the side that is not driven, then maching this side to take the bearing block. That way the thrust bearing will be on the "wrong" side of the screw but it would mean less mods to the router as it stands. What do you think?
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Re: Marchant Dice router no thrust bearings?
a cost effective route to thrust bearings is to use a deep groove roller bearing on the opposite end of the ballscrew to the motor, which is fixed on the ballscrew and anchored to the frame. This is quite common on lower end machines and often gets mistaken for just an end support bearing. It's not ideal but gives a reasonable amount of thrust protection.
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Re: Marchant Dice router no thrust bearings?
How would you attach the bearing to the screw, locktite retainer?
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Re: Marchant Dice router no thrust bearings?
from what i've seen the end of the ballscrew is threaded either internally or externally and a cap screw and retaining plate is used to hold the bearing onto a journal, or simply held on with a nut on an external thread.
Obviously this depends on the quality of the bearing for backlash removal, and is not much good for heavy loads as the bearing is designed for radial loads not axial loads.
If you want the correct method then you need two opposing angular contact bearings in a housing.
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Re: Marchant Dice router no thrust bearings?
How old is this Marchant Dice machine ?
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Re: Marchant Dice router no thrust bearings?
Can you post some photos of the opposite end of the screw so we can see how its mounted?
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2 Attachment(s)
Re: Marchant Dice router no thrust bearings?
Attachment 7938Attachment 7939
Here are some pics of the end mount
I bought the router about a year ago
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Re: Marchant Dice router no thrust bearings?
I wonder if this is where strikecnc got the idea of not using proper bearings on the ballscrews.
Anyway, I think the easiest way to solve this is to buy a pair of FK/FF bearing blocks since so long as the extrusion is long enough you can drill a hole in either side and put the new bearing mounts in. That's assuming the ballscrew end machining is standard, what does it look like?
Also, I'd solder those motor connections as if they work loose whilst the machine is running the stepper driver could be damaged.
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Re: Marchant Dice router no thrust bearings?
It looks as though you have some end float which could be shimmed out.
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Re: Marchant Dice router no thrust bearings?
Thats even worse than I thought it would be. The only thing keeping that bearing in place is the ballscrew and if its whipping about it will start to pull the bearing out as well. The first photo isnt very clear but it doesnt look like there is any kind of nut or circlip holding the ballscrew on the outside of the bearing.
I would either buy or make two bearing mounts and get them fitted but you might have to get some lathe work done on the ballscrew as I cant see it already having threads for a securing nut.
Another option would be to use the bearings blocks on the insides of the gantry and have the shaft lathed to fit between the two blocks, some spacers might be required as well. The two blocks on the inside would remove any sideways play from the ballscrew.
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Re: Marchant Dice router no thrust bearings?
First choice would be Throw the thing in the scrap bin where it belongs and start again.!!. . . OR. . . Failing that A simple fix would be use a thrust bearings at coupler side of profile, presuming the other has deep grove bearing, and thread the shaft and put locking nut on.
Better way would be machine the profile to accept angular contact bearings then thread the shaft and lock nut or use Bearing block machine screw to fit.!
First choice would be best solution.!!. . . . . . If you wan't to know all the hassle coming your way with if you continue with this pile of shite then just contact Micheal (M.Marino) has he's been there and pay'd the price. Honestly not worth the price of the thrust bearings in my experience.!!
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Re: Marchant Dice router no thrust bearings?
a double row angular contact may be a simple compact way forward if you can squeeze one in somewhere
3200 5200 ZZ Series Metal Shielded Double Row Angular Contact Bearings - Choose | eBay
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Re: Marchant Dice router no thrust bearings?
Quote:
Originally Posted by
blackburn mark
These would still need a retaining ring or plate to stop the outer bearing floating.!!
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1 Attachment(s)
Re: Marchant Dice router no thrust bearings?
Attachment 7940
This is what I think I would need machined to take the bearing blocks at the drive side. The top pic shows whats there and the bottom shows what I think I need.
As there is not enough material, I would need to chop the current machined end off and weld a new one in to give me the material I need for the new design.
This is how I have machined my ballscrews before as my lathe aint up to the job of machining the hardend casing off. It makes the maching a lot easier anyway and as the welded on blank is oversized when it is turned down in the lathe it brings itself concentric with the screw.
http://i59.photobucket.com/albums/g2...h/P1070450.jpg
Something like this for the bearing block?
http://www.zappautomation.co.uk/en/f...7-fk08-c7.html
Its a little smaller than the recommended block but I doubt it will matter too much for this router as I am only looking get something in there that will work relative to the limits of the rest of the machine.
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Re: Marchant Dice router no thrust bearings?
Quote:
Originally Posted by
JAZZCNC
These would still need a retaining ring or plate to stop the outer bearing floating.!!
i wasnt thinking old knicker elastic and tape lol
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Re: Marchant Dice router no thrust bearings?
Quote:
Originally Posted by
gavztheouch
This is how I have machined my ballscrews before as my lathe aint up to the job of machining the hardend casing off.
That looks like a Myford lathe and with the correct cutting tool will handle machining ballscrews, my little boxford does. But with this job then it wouldn't hurt to anneal the end up to remove hardening.
From the pics of motor with screw then there is a bit screw left with enough room for a nut so just thread the whole lot then grind flat spot for coupler screw, you may have to machine a new coupler or a sleeve.? . . . Sure it could be done easier than welding bits onto screw.!!
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Re: Marchant Dice router no thrust bearings?
That bearing block from zapp would do nicely. You could fit one either end of the screw on the inside faces. All you would need to do is machine down the shaft to fit the bearing and they would still be long enough to fit back on.
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Re: Marchant Dice router no thrust bearings?
I had one (sold it) with the trapezoid screws on it. From the way that They make their set up you should have just enough to put that FK block in on the inside and if you got an FF block as well for the other end you should be able to get rid of the play with the grub screw and a bevel washer or two (someone correct my spelling of those please). That or you could go with an angular contact bearing on the free with said washer and grub screw. Good luck on getting it to cut better, If that is the model with the unsupported round rails on Y you might want add a plate across that back to improve rigidity.
He has changed design a little bit over the last 4 years, depending on which year model depends on what needs to be done to make it work at anywhere near the capacity that they state it can. Let's just say I was not overly impressed with my machine and the work I had to do on it to get any where near accurate cutting from it, compared to what I was told it was capable of. Hence the reason for the machine I currently use.
Michael
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Re: Marchant Dice router no thrust bearings?
Hi Michael, my machine is around a year old. It has hiwin profile rails on the long axis and unsupported rounds on the other two. Ballscrews on all three axis.
In soft plastic and foam it is really accurate and I can get rapids of 3000mm/min pretty easily and smoothly.
Its really only with harder materials it begins to struggle, luckly I have had quite a lot of work given to me for prototyping in soft plastic which has made the machine pay its way.
I don't know if it is worth modding the machine to be able to process hardwood, I could keep it solely for softplastic and modelling foam. But if I could do it with as little risk to ruining the orginal machine as possible it may be worth the risk and effort.
I think the easiest way to achive this would be a ballscrew support/fixing block from zapp, and to mount this on the side that is not driven. This would mean buying to blocks at about £35 each plus modding the ballscrews. Total cost about £100 and two days work.
Out of interest which machine are you running now Michael?
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Re: Marchant Dice router no thrust bearings?
Michael doesn't use a branded machine, you can read the build log for it here.
http://www.mycncuk.com/forums/router...d-machine.html
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Re: Marchant Dice router no thrust bearings?
http://i59.photobucket.com/albums/g2...pscca74a2f.jpg
http://i59.photobucket.com/albums/g2...ps18edd9f3.jpg
http://i59.photobucket.com/albums/g2...psd528f462.jpg
Digging a little deeper I noticed the ballnut for the x-axis is simply pressed into the extrusion, it looks like friction is the only thing holding it in there.
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Re: Marchant Dice router no thrust bearings?
Quote:
Originally Posted by
gavztheouch
Digging a little deeper I noticed the ballnut for the x-axis is simply pressed into the extrusion, it looks like friction is the only thing holding it in there.
Surprise surprise.!! . . . I've been chastised many times or warned about possible Legal action for calling these machines and always replied " If it ever got to court then my Undefeat-able defence would be the machine it's self " . No court or Engineers report would disagree these machines are Bad and unfit for purpose.!! . . . . . .Totally disgusting the guy should be ashamed.
Just HOPE people looking to buy see this thread and take note.!!
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Re: Marchant Dice router no thrust bearings?
Just HOPE people looking to buy see this thread and... not buy mine :frown: (When I flog it to buy something else.)
Actually do you think I have any rights to make them take the machine back and give me a refund.
Looking back through my emails the invoice is dated 6th of Jan but I didn't recieve the machine until Feb. So I have had the machine for less than a year.
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Re: Marchant Dice router no thrust bearings?
I could put you in contact with a few advocates but you would have to move quickly due to the time issue. Though the fit for purpose (FFP) issue might be different up here in Scotland and you might wish to look into it. personally I sold mine as is and documented the limitations to the buyer (that way I am being honest to the next guy down the line). There is no way, given an machinist and industrial engineer's opinion in court that they would win on a FFP case. Not on their smaller hobby units, that I was told would have no problem handling acrylic and hard woods.
Michaael
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Re: Marchant Dice router no thrust bearings?
Quote:
Originally Posted by
gavztheouch
Actually do you think I have any rights to make them take the machine back and give me a refund.
Looking back through my emails the invoice is dated 6th of Jan but I didn't recieve the machine until Feb. So I have had the machine for less than a year.
Not really after nearly a year.!! . . . . Thou you could contact him and say how upset you are about the disgusting quality of build and see what he says or his prepared to do help ease the pain.?
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Re: Marchant Dice router no thrust bearings?
These make Strikes attempt look passable!
Marchant Dice? More like Rip Off Marchant. C$£ts!
If you don't mind me asking how much did they charge for that? I'm guessing about £2000?
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Re: Marchant Dice router no thrust bearings?
Close to £2000 yeah.
I think the complete system was £4000 for the extra £2000 you get a shite pc with mach and three stepper drivers.
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Re: Marchant Dice router no thrust bearings?
Quote:
Originally Posted by
gavztheouch
Close to £2000 yeah.
How F@~$ing much. . . .and you didn't even get drives.? . . . .What did you get for nearly 2K.
Working on those prices the machine I made for Micheal would be £30,000. . . :hysterical:
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Re: Marchant Dice router no thrust bearings?
Everything in the pictures including the motors. No electronics.
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Re: Marchant Dice router no thrust bearings?
I'mnot wanting to defend Marchant's machines, but press fit works fine if done right. There are far more critical machines relying solely on pressfit to keep things together.
As for the lack of thrust bearings, I've got a lathe that would of cost far more than a few thousand in todays money that relies on the stepper motor bearings to hold ballscrews in place. It's not ideal, and most likely will have an effect on longitivity, but it works.
I am wanting to upgrade my lathe, but it's still currently rattling out lots of parts bang on size without any issues.
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Re: Marchant Dice router no thrust bearings?
Quote:
Originally Posted by
m_c
I'mnot wanting to defend Marchant's machines, but press fit works fine if done right. There are far more critical machines relying solely on pressfit to keep things together.
Think you'll be hard pressed to any commercial or even serious Hobby CNC machine that press fit Ballnuts or run ballscrews without some form of end fixing.?? . . . It's Bad practice pure and simple and proper manufacturer wouldn't do it.!
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Re: Marchant Dice router no thrust bearings?
What size machine is this we are talking about ?
Press fit is fine provided it's pressed into something substantial, pressing a bearing into a length of licorice extrusion doesn't cut it with me.
Also stepper motors have one bearing pre loaded with a wavy washer to allow for expansion, any design that relies on this setup of deep grooved bearings and flexible thrust again isn't good design.
I can understand cutting corners to save money, many make that mistake but at these prices quoted they are not cutting corners to save money they are fleecing customers who believe all the bullshģt
