Rebuttal Post - Reports of M&R AC Print-Head Issues

pwalsh · July 5th, 2011, 08:35 AM

There’s been a lot posted on DigitSmith over the past year or so about new technology and design elements of various machines. Recently we’ve seen a post by a respected member warning potential purchasers of M&R equipment of a potential design flaw in the way that M&R mounts the drive system on their AC print-heads.

Essentially the “Expert” is posting his opinions that the method used by M&R to mount their right angle worm reduction gearbox’s (WRG’s) with the electric motor facing vertically down, is a design flaw. Our expert goes way beyond criticizing the approach that M&R uses, by promoting the methodology used by a competitive manufacturer that totally avoids the use of a WGR, in favor of using a simple system of a toothed drive belt to achieve a geared reduction between the drive motor and the intermediate pulley to drive the print-head.

A few important questions that the expert did not address in his post, that are worth additional consideration include:

Is the method that M&R is using to mount these WGR’s with the electric motor mounted vertically down, a manufacturer approved method?
What is the “Mean Time Between Failure” (MTBF), and primary cause of failure that M&R has experienced from mounting WGR’s this way?
Why does M&R utilize a more expensive WGR in their design when a simpler system of a toothed belt and pulley reduction is available?
What additional level of friction and inefficiency is created by using a toothed drive belt versus the minimal drag of a lubricated WGR?
What MTBF, or other issues with their drive mechanism has this alternative manufacturer experienced?

Spider-Machines · July 5th, 2011, 08:44 AM

Nice post Peter ... it's nice to see you back :-)

Here is my reply ...

The fact that the Vice-President of NaZdar is taking an hour -or- more to reply to design flaw issues with M&R A/C Printheads means that Printex is winning the game :-D

FACT ... people are choosing Printex over M&R for more reasons than just drive belts :-@

BTW ... it's nice to see you back :-p

Here is some of the info from the thread Peter is referring to:

Quote:

Originally Posted by preston

Not really. Take the sportsman for example. On the ac print heads M&R uses a 90 degree gear reduction. The problem is they mount it with the motor down. This is not the best way for several reasons but the main thing is the oil is not sitting in the sump correctly and the oil seal between the gear reduction and motor is constantly submersed under the oil. So what happens when the oil seal starts to fail? Well the first thing is oil starts running down all over the motor. Not good. Now comes the serviceability of this type setup. You have to unbolt the heavy assembly, disconnect all the drive stuff to the squeegee/floodbar carriage and remove the gear drive and motor from the print arm. Now you have to remove the motor, drain the oil from the gear reduction, open it up, remove the gears and bearing, knock out the oil seal, replace it, put the whole thing back together and remount it. A lot of work for something that should never have been mounted that way in the first place.

With the Printex there is no oil to leak, no heavy gear reduction. If ever needed changing the reduction pulley belt is quick and simple. The ac motor is also very easy to replace if needed.

Quote:

Originally Posted by Spider-Machines

I found this pic that shows what you are describing ...

Thanks for such an informative post Preston ... it explains why we see a lot of these GearBox issues in the field ... Do you know if M&R has addressed this known problem with their A/C Printheads :-?

Once again thanks for bringing it to light :-))

Quote:

Originally Posted by preston

No spin as I did not say it had to be done every week. But when it needs to be done it is a lot of work and takes a long time. This cost you not only in down time but if you are paying a tech it cost you more if it takes him longer. Also on the sportsman the only way to adjust the belt tension is by loosening the angle drive gear box mount plate and then using a pry bar to slide it back on the slotted bolt holes. Again, time and money.

On the Printex you just lift up the front screen clamp and adjust the belt with a 10 mm wrench. Simple, fast and cost effective.

This is the point of this thread. To show how the design of the printex saves you tons of time when and if you need to repair something. Most things are so simple you do not even need to get a tech in to do it. Becasue it is such a well thought out design things can be repaired or adjusted fast if needed. This means less downtime and that means you are making more money because your press is not down for a long time during repairs or adjustments.

The sportsman is a great press but when it breaks down it is going to cost you a lot.

Quote:

Originally Posted by Spider-Machines

Preston this is an excellent post ...

The really interesting point about the design is that you could own a Printex and literally never have to remove the A/C motors no matter how many millions -and- millions of prints <--- that has tremendous value :-))

A belt change would be as simple as (4) bolts with a Jack Screw to set proper tension :-D

Spider-Machines · July 5th, 2011, 09:16 AM

Quote:

Originally Posted by inkman996

Awesome post Peter it is sad tho that said expert instead of refuting any of your distinctions had to resort to his usual attack.

What's there to refute ... you are big on common sense right?

Apply common sense ...

A. The oil resting on the seal will eventually leak out (gravity is common sense)

B. if the gear box were mounted horizontally the movement within the gearbox would sling/pump/splash the oil around correctly (common sense)

C. If the gear box were mounted vertically the motor would be sticking up so even if the seal were damaged it wouldn't leak down the sides of the motor (more common sense)

Spiderman has to get on a Video Skype Conference Call with Austria in a bit ... Marcodie is inches away from the USA market ... Boy won't that be FUN :-))

pwalsh · July 5th, 2011, 09:52 AM

Quote:

Originally Posted by Spider-Machines

Nice post Peter ... it's nice to see you back :-)

Here is my reply ...

The fact that the Vice-President of NaZdar is taking an hour -or- more to reply to design flaw issues with M&R A/C Print-heads means that Printex is winning the game :-D

FACT ... people are choosing Printex over M&R for more reasons than just drive belts :-@

BTW ... it's nice to see you back :-p

Here is some of the info from the thread Peter is referring to:

Robert: I'm back because the DigitSmith Site Administrators have implemented a level of moderation that curtails the personal attacks, and spread of blatantly false information. Your guy posted a lot of information on the design that M&R used for their AC print-head drives, and even went as far as to suggest that the system that another manufacturer is using is more effective.

I refute the points that were made in the original post and have responded with a series of specific questions related to the design that M&R and PrintEx are using on their AC drive print-heads. I’d greatly appreciate getting “Qualified” answers to these specific questions rather than you just reposting the original unsubstantiated statements.

Is the method that M&R is using to mount these WGR’s with the electric motor mounted vertically down, a manufacturer approved method?
What is the “Mean Time Between Failure” (MTBF), and primary cause of failure that M&R has experienced from mounting WGR’s this way?
Why does M&R utilize a more expensive WGR in their design when a simpler system of a toothed belt and pulley reduction is available?
What additional level of friction and inefficiency is created by using a toothed drive belt versus the minimal drag of a lubricated WGR?
What MTBF, or other issues with their drive mechanism has this alternative manufacturer experienced?

BTW, Here’s a couple of additional questions to add to the list:

Do you realize that M&R’s original AC print-head drives from 10+ years ago used a very similar drive belt and reduction pulley system to what PrintEx uses today?
Do you think there’s a possibility that M&R learned something about this design approach that drove their decision to move to a more expensive AC drive system that utilizes a worm gear reducer?

Spider-Machines · July 5th, 2011, 10:52 AM

Quote:

Originally Posted by pwalsh

Robert: I'm back because the DigitSmith Site Administrators have implemented a level of moderation that curtails the personal attacks, and spread of blatantly false information. Your guy posted a lot of information on the design that M&R used for their AC print-head drives, and even went as far as to suggest that the system that another manufacturer is using is more effective.

I refute the points that were made in the original post and have responded with a series of specific questions related to the design that M&R and PrintEx are using on their AC drive print-heads. I’d greatly appreciate getting “Qualified” answers to these specific questions rather than you just reposting the original unsubstantiated statements.

Is the method that M&R is using to mount these WGR’s with the electric motor mounted vertically down, a manufacturer approved method?
What is the “Mean Time Between Failure” (MTBF), and primary cause of failure that M&R has experienced from mounting WGR’s this way?
Why does M&R utilize a more expensive WGR in their design when a simpler system of a toothed belt and pulley reduction is available?
What additional level of friction and inefficiency is created by using a toothed drive belt versus the minimal drag of a lubricated WGR?
What MTBF, or other issues with their drive mechanism has this alternative manufacturer experienced?

BTW, Here’s a couple of additional questions to add to the list:

Do you realize that M&R’s original AC print-head drives from 10+ years ago used a very similar drive belt and reduction pulley system to what PrintEx uses today?
Do you think there’s a possibility that M&R learned something about this design approach that drove their decision to move to a more expensive AC drive system that utilizes a worm gear reducer?

Is the method that M&R is using to mount these WGR’s with the electric motor mounted vertically down, a manufacturer approved method?

approved isn't the point ... when designing equipment we make choices that are less than optimal ... M&R has made such a choice -and- unfortunately M&R customers are paying that price with leaking GearBoxes throughout the world :-((
What is the “Mean Time Between Failure” (MTBF), and primary cause of failure that M&R has experienced from mounting WGR’s this way?

Lets give M&R the benefit of the doubt -and- assume that the GearBox will not leak before the belt needs to be change ... we'll call it even on a time/use basis ... its easier to change a belt -than- rebuild a Gear Box -nad- a heck of a lot cheaper to buy a new belt -than- to buy a $500 Gear Box
Why does M&R utilize a more expensive WGR in their design when a simpler system of a toothed belt and pulley reduction is available?

cost ... its cheaper for M&R to buy a mass produced GearBox -than- to MFG the parts to build the Belt System
What additional level of friction and inefficiency is created by using a toothed drive belt versus the minimal drag of a lubricated WGR?

Minimal Drag? Have you ever tried to manually pull the printhead on an M&R compared to the Printex ... talk about SPIN :-o
What MTBF, or other issues with their drive mechanism has this alternative manufacturer experienced?

This one is Laughable ... there are Belts just like these with millions of rotational inches/feet/miles ... (Belt Life is not a topic you can win a debate on)
Do you realize that M&R’s original AC print-head drives from 10+ years ago used a very similar drive belt and reduction pulley system to what PrintEx uses today?

yup ... are you saying that M&R customers were experiencing catastrophic failure so M&R switched ... I think not ... as I posted above ... M&R went with a mass produced Gear Box to reduce their costs -and- increase their profit :-p
Do you think there’s a possibility that M&R learned something about this design approach that drove their decision to move to a more expensive AC drive system that utilizes a worm gear reducer?

if M&R was having application issues with its Belt Design it my very well have been its design NOT the Belt Power Transmission (once again Belt Life / use is NOT a topic you will win a debate on) ... Belts are used in far worse applications than screen printing machines and last for decades ... doesn't M&R use drive belts in conjunction with the GrearBox (nuf said)

Printwizard · July 5th, 2011, 10:58 AM

Quote:

Originally Posted by screenmachines

So which is it, Printex, Marcodie, or the China machine. Crazy how you think they all are the best. Please pick a product and stick with it. It's just hard to keep up with your product choice.

I thought TAS being mainly built of common parts would have no maintenance issues. The ones I have seen seem to actually have a longer production life as you see a lot of old TAS still chugging out the work beside mothballed gauntlets. (India)

SCREENMACHINES, Great call, pick a brand. I think last week the mention was SRoque as well. Logic dictates any buyer will look at supply chain and downstream parts and profitiblilty of a company so it will still be there to service, and locally techs can support, and a second hand demand which only comes with a critical mass and a profitable, reputable manufacturer. You can't do that with twenty factories that all have a dozen presses in the market, you would grow and sell easier one manufacturer and get 240 presses in the market, then you would get better manufacturer support, marketing, and it would snowball with the critical mass. The shotgun approach of being all things to all people is not good business sense, next week will RWB be pitching us offset flex machines in case we want to go into printing plastic bags?

NAZDAR, great questions, this is the comparison we need more of, and across more brands.
RWB, Great answers. Explained and understandable. It's not about the person, it's all about the machine.

pwalsh · July 5th, 2011, 11:23 AM

Quote:

Originally Posted by Spider-Machines

Is the method that M&R is using to mount these WGR’s with the electric motor mounted vertically down, a manufacturer approved method?

approved isn't the point ... when designing equipment we make choices that are less than optimal ... M&R has made such a choice -and- unfortunately M&R customers are paying that price with leaking GearBoxes throughout the world :-((
What is the “Mean Time Between Failure” (MTBF), and primary cause of failure that M&R has experienced from mounting WGR’s this way?

Lets give M&R the benefit of the doubt -and- assume that the GearBox will not leak before the belt needs to be change ... we'll call it even on a time/use basis ... its easier to change a belt -than- rebuild a Gear Box -nad- a heck of a lot cheaper to buy a new belt -than- to buy a $500 Gear Box
Why does M&R utilize a more expensive WGR in their design when a simpler system of a toothed belt and pulley reduction is available?

cost ... its cheaper for M&R to buy a mass produced GearBox -than- to MFG the parts to build the Belt System
What additional level of friction and inefficiency is created by using a toothed drive belt versus the minimal drag of a lubricated WGR?

Minimal Drag? Have you ever tried to manually pull the printhead on an M&R compared to the Printex ... talk about SPIN :-o
What MTBF, or other issues with their drive mechanism has this alternative manufacturer experienced?

This one is Laughable ... there are Belts just like these with millions of rotational inches/feet/miles ... (Belt Life is not a topic you can win a debate on)
Do you realize that M&R’s original AC print-head drives from 10+ years ago used a very similar drive belt and reduction pulley system to what PrintEx uses today?

yup ... are you saying that M&R customers were experiencing catastrophic failure so M&R switched ... I think not ... as I posted above ... M&R went with a mass produced Gear Box to reduce their costs -and- increase their profit :-p
Do you think there’s a possibility that M&R learned something about this design approach that drove their decision to move to a more expensive AC drive system that utilizes a worm gear reducer?

if M&R was having application issues with its Belt Design it my very well have been its design NOT the Belt Power Transmission (once again Belt Life / use is NOT a topic you will win a debate on) ... Belts are used in far worse applications than screen printing machines and last for decades ... doesn't M&R use drive belts in conjunction with the GrearBox (nuf said)

Robert: This civil response is a positive development that I thank you for, and it would have been even better if the information that you had provided was accurate and correct.

For example the fact that you can push or pull a PrintEx print-head by hand has everything to do with the different gear ratios being used than it does with “belt and pulley” versus worm gear reducer.

So why would M&R use a much lower ratio than PrintEx? Could it be that it allows the AC motor to spin at higher RPM’s allowing the motor to develop higher torque, and for the cooling fan on the motor to work more effectively? His is an issue where it would be great to have Preston’s input on.

And what are you smoking with your assertion that it’s less expensive for M&R to purchase a worm gear reducer than it would be for them to utilize a cheaper system of a belt and pulley? Are you suggesting that M&R couldn’t purchase a mass produced belt and pulley system than the current worm gear reducer?

Spider-Machines · July 5th, 2011, 11:39 AM

Quote:

Originally Posted by pwalsh

Robert: This civil response is a positive development that I thank you for, and it would have been even better if the information that you had provided was accurate and correct.

For example the fact that you can push or pull a PrintEx print-head by hand has everything to do with the different gear ratios being used than it does with “belt and pulley” versus worm gear reducer.

So why would M&R use a much lower ratio than PrintEx? Could it be that it allows the AC motor to spin at higher RPM’s allowing the motor to develop higher torque, and for the cooling fan on the motor to work more effectively? His is an issue where it would be great to have Preston’s input on.

And what are you smoking with your assertion that it’s less expensive for M&R to purchase a worm gear reducer than it would be for them to utilize a cheaper system of a belt and pulley? Are you suggesting that M&R couldn’t purchase a mass produced belt and pulley system than the current worm gear reducer?

Robert: This civil response is a positive development that I thank you for, and it would have been even better if the information that you had provided was accurate and correct.

GFY ... Just kidding ;-) LOL <--- welcome back Peter

For example the fact that you can push or pull a PrintEx print-head by hand has everything to do with the different gear ratios being used than it does with “belt and pulley” versus worm gear reducer.

it actually has everything to do with the mechanics of worm gear itself <--- really suprised you didn't know that (have you never rebuilt one of these -or- do you just sell'em a replacement GearBox :-?

So why would M&R use a much lower ratio than PrintEx? Could it be that it allows the AC motor to spin at higher RPM’s allowing the motor to develop higher torque, and for the cooling fan on the motor to work more effectively? His is an issue where it would be great to have Preston’s input on.

you are kidding right ... you are aware that the windings/Hz/rotational speeds are almost identical on the Printex -vs- M&R ... post pics of the GearBox -and- the Ratios -and- we can do a fair comparison of your thesis

And what are you smoking with your assertion that it’s less expensive for M&R to purchase a worm gear reducer than it would be for them to utilize a cheaper system of a belt and pulley? Are you suggesting that M&R couldn’t purchase a mass produced belt and pulley system than the current worm gear reducer?

I don't smoke ... never have -and- never will ... I can absolutely stand by my statement ... by M&R buying a cheap mass produced GearBox it is less cost than M&R making the necessary parts in-house -and- installing them correctly in the final assembly (this is by far the biggest issue that M&R faced in deciding to go with a cheap GearBox)

pwalsh · July 5th, 2011, 12:34 PM

Quote:

Originally Posted by Spider-Machines

For example the fact that you can push or pull a PrintEx print-head by hand has everything to do with the different gear ratios being used than it does with “belt and pulley” versus worm gear reducer.

it actually has everything to do with the mechanics of worm gear itself <--- really surprised you didn't know that (have you never rebuilt one of these -or- do you just sell'em a replacement GearBox :-?

PW Response: Actually I’ve built and rebuilt many hundreds, maybe even more than a thousand Worm Gear Reducers to include the small format units used on the M&R press though to large format gear reducers used on industrial drive systems. Here’s a snippet of information for you. I’ve only had three jobs in my career to include; 16 years with the Nazdar Company, 9+ years with TAS, and before that 10 years with Renold Australia (www.renold.com.au) one of the world’s leaders in industrial transmission products. So, your question about my experience in this area is a just a little off base.

So why would M&R use a much lower ratio than PrintEx? Could it be that it allows the AC motor to spin at higher RPM’s allowing the motor to develop higher torque, and for the cooling fan on the motor to work more effectively? His is an issue where it would be great to have Preston’s input on.

you are kidding right ... you are aware that the windings/Hz/rotational speeds are almost identical on the Printex -vs- M&R ... post pics of the GearBox -and- the Ratios -and- we can do a fair comparison of your thesis

PW Response: I’ll concede the point that the RPM of the electric motors on the M&R and PrintEx could be similar at max speed, but that isn’t how screen-printers run their presses. The AC drives are operated at much lower speeds, especially when using heavy bodied plastisol inks such as whites, high density, and other specialty products. It’s in these applications where a worm gear reducer with the appropriate ratio for the application will significantly reduce the stress on the motor by allowing it to rotate faster at slower print stroke speeds.

And what are you smoking with your assertion that it’s less expensive for M&R to purchase a worm gear reducer than it would be for them to utilize a cheaper system of a belt and pulley? Are you suggesting that M&R couldn’t purchase a mass produced belt and pulley system than the current worm gear reducer?

I don't smoke ... never have -and- never will ... I can absolutely stand by my statement ... by M&R buying a cheap mass produced GearBox it is less cost than M&R making the necessary parts in-house -and- installing them correctly in the final assembly (this is by far the biggest issue that M&R faced in deciding to go with a cheap GearBox)

PW Response: You’re welcome to stand by your position, but you are still wrong. Do you honestly expect people to accept your position that M&R would produce their own pulley’s “In-House” versus sourcing them from a mass producing manufacturer on the open market? What other components and assembly would be involved that couldn’t be cost effectively produced at M&R? After all they previously used a direct drive belt and pulley system more than 10 years ago. If M&R ever decided to go back to the drive belt and pulley system that PrintEx is using, I have no doubt that they could do it at a lower cost than the worm gear reducer that they currently use.

Robert: Please see above for qualifiied responses to your post, and that's what I have to say on this issue.

Spider-Machines · July 5th, 2011, 12:43 PM

Quote:

Originally Posted by Printwizard

I thought TAS being mainly built of common parts would have no maintenance issues. The ones I have seen seem to actually have a longer production life as you see a lot of old TAS still chugging out the work beside mothballed gauntlets. (India)

SCREENMACHINES, Great call, pick a brand. I think last week the mention was SRoque as well. Logic dictates any buyer will look at supply chain and downstream parts and profitiblilty of a company so it will still be there to service, and locally techs can support, and a second hand demand which only comes with a critical mass and a profitable, reputable manufacturer. You can't do that with twenty factories that all have a dozen presses in the market, you would grow and sell easier one manufacturer and get 240 presses in the market, then you would get better manufacturer support, marketing, and it would snowball with the critical mass. The shotgun approach of being all things to all people is not good business sense, next week will RWB be pitching us offset flex machines in case we want to go into printing plastic bags?

NAZDAR, great questions, this is the comparison we need more of, and across more brands.
RWB, Great answers. Explained and understandable. It's not about the person, it's all about the machine.

Wiz ... you are WRONG about the different brands ... Printex has its Market in the USA (Buyers of Sportsman EX Buyers -and- Challenger III) ... Marcodie has its Market in the USA (Alpha8 Buyers) ... China Sporty has its Market in the USA (Buyers of Used Gauntlet II, Sportsman, etc.)