MechMate CNC Router Forum

Go Back   MechMate CNC Router Forum > Personal Build Histories > MechMates already cutting
Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Reply
 
Thread Tools
  #1  
Old Sat 12 June 2010, 03:17
Red_boards
Just call me: Red #91
 
Melbourne
Australia
First surfboard out of big block #91 - Melbourne, AU

After a year or so of looking around, including investigation into importing a machine from China, I've decided (and got full support of the better half!) to build a MM. While I could have landed the Chinese machine for something like $17000 (Aus), the questions they asked through the process made me think, "what if something goes wrong", and "what's the quality of the machine?" I figured I was better off putting my (very) limited mechanical and electronic abilities to work and produce a piece of equipment that I know and understand. I'm aiming to keep the build as simple as possible.

My initial concern is about chatter. I'm planning to start with a Makita 3612C router and am considering running MotionKing 9802 motors with PMDX125 BOB and Gecko G203V's.

I'm going to be 3D cutting polystyrene mostly (a bit of veneers and other wood occasionally) - surfboards using a 350mm z axis.

My question is whether running the MK motors ungeared with a 10-20k rpm router is likely to result in chatter marks on foam.

Should I pay 3x as much and opt for the Oriental Motors 7.2 geared option for better control over microstepping?
Reply With Quote
  #2  
Old Sat 12 June 2010, 13:57
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Red,
Experience tells me you shouldn't really notice the chatter on the foam, but for your use, I would suggest fabricating the 3:1 belt reduction units. They are very affordable and offer great reduction in chatter.

Many different styles are presented in the forum. The plus side is you can build your MM with direct drive units and then use the MM to upgrade to the belts if you need it.

Either way, you have an affordable path to a great performing machine.

Sean
Reply With Quote
  #3  
Old Sun 13 June 2010, 03:19
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Thank you, Sean
Direct then upgrade sounds like a sensible way to go.
I have been daunted at the thought of trying to build the belt drive units first off.

Better get to bed now - up at 3.30am to go down the pub to watch Australia take on Germany in the football world cup
Reply With Quote
  #4  
Old Sun 13 June 2010, 07:13
rotorzoomer
Just call me: Account - DISABLED
 
Account - DISABLED
Australia
Router

Hold onto that Makita 3612C...word on the street from my research at tool shops is that the newer models (Australian Editions Only) are amongst the worst Makita have brought out in a long time.
Reply With Quote
  #5  
Old Fri 18 June 2010, 05:33
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Router,
Thanks. Since I don't yet have one in my hand I'll try to shop around and get "old stock".
Reply With Quote
  #6  
Old Fri 18 June 2010, 05:44
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Table steel

Getting the steel order ready.
I see that the plans have pipe for cross braces, but many are using box around 50x50x3mm.
Apart from the difference in dust retention of box over pipe, is the preference for box because it's easier to deal with for squaring things up

Many years ago I learnt the difference between theory and reality when I got into surfboard manufacture. All of a sudden those 1/8" decisions were important for the final result. Getting that learning curve feeling all over again.
Reply With Quote
  #7  
Old Sun 27 June 2010, 09:35
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Errata in plans

Plan #10 40 014 title should be 350mm (14") Z-SLIDE ASSEMBLY
Or has this been pointed out a hundred times already?
Reply With Quote
  #8  
Old Sun 27 June 2010, 09:43
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Y rail clamp strip question

What is the purpose of the y-rail clamp strip?
Is this to take tapped holes or to help with rigidity of the cross member tube? (or both?)
Reply With Quote
  #9  
Old Sun 27 June 2010, 16:12
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
The y tube sections which are 50mm x 100mm (or 2" x 4") have a small wall thickness, thus not enough material to tap threads. The clamp strip is essentially a "row of captive nuts" inside the tube. Absolutely needed for assembly of rails-on-tube for the gantry.

Some on this forum have increased the tube gauge so the wall thickness was at least 3/16" or 1/4"- thus allowing for the 5/16" tapped holes in the tube and omit the clamp strip.

This added mass does change the performance of the machine slightly, but not noticeable on the 3 machines I have built with 7.2 geared motors.

I hope this answers your question.

Sean
Reply With Quote
  #10  
Old Wed 30 June 2010, 23:20
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Thanks, Sean
That's what I was thinking it did, but I could not get it 100% clear from the plans.
Reply With Quote
  #11  
Old Thu 01 July 2010, 00:01
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Power Supply question

Calculating power needs and found first mistake*. 10 minutes after ordering the Motion King motors I realised that I had made an error in the motor type ordered. Trying to get it changed before it ships...
Good thing is that I caught the motor ordering error because I was working through the power supply calculations.

The more I read the confuseder I get, so I'd appreciate a clarification.
There is some good info on power for the Motion King 34HS9801 motors, namely this one from Mike (Richards):
Quote:
The Motion King 34HS9801 motor is rated 4.1mH, so, if you wire it half-coil, you could use a power supply of up to 65VDC. 42VDC should be perfectly adequate, although I would probably select a 50VDC power supply as a good compromise between excessive heat and maximum speed. A transformer with a 35VAC winding would give you about 50VDC
I see that Surfer and Ries have used a 500VA transformer and wired the two 42Volt outputs in parallel to get the end voltages around 59.5VAC.http://www.mechmate.com/forums/showt...31&postcount=5

My (sqrt4.1 mH *32) calculation take me to 65V(DC) Max for the motors. Using a 75% factor (confused whether to apply this because Mike says yes and Gerald is "less" supportive) comes to 49V(DC) which translates to 35V(AC)

The motors are rated at 4A, so the power should be 35V(AC)*16A = 560VA
This compares OK to the 514VA I got using Gerald's method.

My questions are:
I think I'm looking for at least 500VA, 50V(DC) 35V(AC) power supply. It seems bigger than many are using. Is it about right or do I need to go bigger or smaller?

Much appreciated
Red

*Actually it's mistake #2, but the first was just too idiotic!
I gave PMD the incorrect delivery address for the PMDX125 and Gecko 203V bundle I ordered. Had a week of fun chasing Australia Post to get my delivery. Steve at PMD was very helpful and didn't even call me an idiot (but my wife did!)
Reply With Quote
  #12  
Old Thu 01 July 2010, 01:55
guerd87
Just call me: John, Still trying to earn a #
 
Pakenham, VIC
Australia
Ive only just found your thread, Looking forward to seeing your build. Where abouts in Melbourne are you located? Im down in Pakenham. Im ordering my motors and drivers next week and ready to start on the machine
Reply With Quote
  #13  
Old Thu 01 July 2010, 02:18
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Hi John,
I'm in Carnegie.
I have laser cut parts from Rick (RNixon), BOB and drivers and some other bits and pieces. I'm getting quotes for steel and assembling tools at the moment.

But the power supply problem (see post #11) is troubling me. I'm equally concerned with going too high V (frying motors) and too low (stalled motors).
Reply With Quote
  #14  
Old Thu 01 July 2010, 02:54
guerd87
Just call me: John, Still trying to earn a #
 
Pakenham, VIC
Australia
From my reading I have decided to go close to the motor specs and go for a 45VAC, with around 63VDC. Using the VA calculator methods thats nearly 1000VA! I was told, from experiance, that a 300VA would be fine. 500's are more popular so im just going for one of them. (check my thread in Intro's)

I am also going to get my parts from Rick and currently planning my steel order. What table size are you using? I originally wanted 2400 x 1200 but I am thinking of adding an extra bit on the end with an alloy bed to use for alloy engraving and light machining. I dont want to have coolant all over my normal bed.
Reply With Quote
  #15  
Old Sat 03 July 2010, 06:51
KenC
Just call me: Ken
 
Klang
Malaysia
Red, The formula is just a guide, you don't have to be exact & you don't neet to de-rate by 75%. The motor can in fact work happily at higher voltage or lower. Only affect the possible efficiency which is not a significant issue with our particular application. but you do need to be sure that the driver will take this voltage too.
BTW, it will be near impossible to match everything seamlessly. The main use of the calc is a guide to minimise the chances of smoke raising when we turn on the power.
Reply With Quote
  #16  
Old Sat 03 July 2010, 09:50
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
If the voltage is too high (motors get too hot for your application and personal taste) then reduce the current setting at the drive. Quite simple, only a few cents for the resistor.

If the voltage is too low (motors are cool, and you can't reach the speeds you want) then you need to replace the transformer (+maybe capacitors) in the power supply. Not so simple, and quite expensive.
Reply With Quote
  #17  
Old Sun 04 July 2010, 23:22
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Thanks for the responses on the PS. After sleeping on it (well actually lying awake at night thinking about it) I decided that I could run power sub-optimally and upgrade later if necessary when I had a feel for things. Your answers helped cement that conclusion. I like the thinking on using resisters to manage amps in.

I bought the bits on Saturday. Went with a 500VA, 45+45V toroid and 1000V, 35A bridge rectifier and 4x5000uF capacitors in parallel. The latter entailed purchase of a small PCB card for mounting and soldering iron (so now you see the limits of my skill and tools!). Luckily my wife was an electronics engineer so is happy about the soldering (but less happy about working with high Amps, so that part's up to me).

Got the motor order changed, so I'm awaiting arrival of the MK motors.

Steel order out for quotes. Some other bits to buy (fasteners, bearings, racks, levelling feet) and about time to get the computer running Mach3.

Fun's about to start...

Last edited by Red_boards; Sun 04 July 2010 at 23:24.. Reason: edit volts to amps in para 1
Reply With Quote
  #18  
Old Sat 10 July 2010, 01:35
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Smile Power supply producing 60v(DC)

Took a deep breath, went to Alltronics, troubled the staff for a couple of hours and walked out with about $250 of bits and pieces. Spent a bit of time reading, re-reading forums, looking at pictures and then with wire strippers and other weapons of destruction. Wired the 500VA, 45+45v toroid transformer in parallel, dropped the rectifier in, clipped and soldered the capacitors on a board in parallel and connected them all together.

Ended up with a PS that produces 60V. Now for getting the Gecko 203v's and PMDX connected...expect lots of questions.
Attached Images
File Type: jpg Red's power supply.JPG (32.7 KB, 3176 views)
File Type: jpg Reds rectifier circuit.jpg (138.9 KB, 3219 views)

Last edited by Red_boards; Sat 10 July 2010 at 01:42.. Reason: attach pictures
Reply With Quote
  #19  
Old Sat 10 July 2010, 01:57
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Schematic overview of electronics

I've struggled to find an intuitive diagram of the electronics (I did find Alan_c's old diagram proposal, which is most useful, and numerous other snippets of useful information).

I've attached my schematic. I've omitted emergency stops and such like at this point.

I think I'm missing a couple of wires into the Gecko, otherwise I'm hoping that it's more or less correct (still have to re-read the manuals).

I'd appreciate any input.
Attached Images
File Type: jpg electronics schematic.JPG (40.5 KB, 3182 views)

Last edited by Red_boards; Sat 10 July 2010 at 02:01.. Reason: affix attachments
Reply With Quote
  #20  
Old Sat 10 July 2010, 13:31
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
There are no more wires to the gecko....one terminal stays disconnected and the last two have a resistor across them.
Reply With Quote
  #21  
Old Sun 11 July 2010, 20:02
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Thank, Gerald.
I remember reading one of your posts where you talk about 9 connections to the Geckos, so I thought I had it OK with the 9 in the diagram. I also saw the resistor in some pics and indication of fusing on the power in, but was not sure how either/both apply to the 203's since the pics were 201's.
The "must read" threads have been great, thanks for setting them up, and thanks to Mike for continueing the facility.
I'll report back when I've done a bit more reading (first I have to do some "real" work).

Current urgent task is to get the steel order modified for the wider dimensions to cater for the 300 x 90 PFC longitudinal beams. I'm going for a short trip to China in 2 weeks and would like to have the steel cluttering up the front yard before then.

Hopefully the motors arrive soon and I can hook the system up to the computer I've been busy rebuilding for the task - a nice simple Pentium desktop running Windows XP.

PS: loaded 32 bit Win7 on my 5 year old "design" computer (lots of RAM and a good graphics card) and got errors saying that Win7 could not access the advanced features of the graphics card. Back to Win XP for than machine, too.
Reply With Quote
  #22  
Old Sun 25 July 2010, 06:32
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Quote:
Originally Posted by rotorzoomer View Post
Hold onto that Makita 3612C...word on the street from my research at tool shops is that the newer models (Australian Editions Only) are amongst the worst Makita have brought out in a long time.
I discovered there's no go on finding one of those these days.
Shopping for alternatives. The advice has been either tye Makita RP2301FC or the Hitachi M12V2
A while to go yet, so I can defer the decision, but I'm interested in other experience/expertise. Thanks
Reply With Quote
  #23  
Old Sun 25 July 2010, 06:50
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Computer rebuild problems - and solutions

Last week I went to clean up the software on an old machine running Win2000. The old "add/remove" programs was broken (common problem, it seems) and the way to fix it is to buy a utility or reinstall/repair the operating system.

Went shopping for Win XP. Like Win XP because it by now has most of the bugs removed. Found that the going rate is about $60 and the e-Bay sellers tend to try to force you above that. Got an OEM version "retail" for A$60. OEM is fine if you have (re)assembled the computer (open it and pull out and plug in a few cables if you wish to subscribe to the letter of the law). It's identical to the retail version.

Went to install and found the computer would not start. Just a hum, a beep and nothing. Disconnected floppy drives, hard drive, etc and try again. Nothing. Reseat graphics card - still nothing. Pull out RAM. Clean and re-seat. Motherboard enters POST (power on self test) and things show up on the screen. Turns out poorly seated RAM can cause the motherboard to decline to fire up.

After a few more attempts, systematically attaching bits and restarting (at about 20 minutes each cycle - more because I was trying to get some work done at the same time) got the computer up and stable and several days later I have the thing more or less clean and ready for CAM software.

Motors arrive this week. Better get the BOB and Geckos wired up and see whether I can get motors co-operating before I leave Friday for China.
Reply With Quote
  #24  
Old Sun 25 July 2010, 08:12
KenC
Just call me: Ken
 
Klang
Malaysia
Scrounging for old PC is fun & challenging at times... not that PCs are expensive, but satisfaction of resurrecting old PCs for a good course is priceless.
Reply With Quote
  #25  
Old Sun 25 July 2010, 20:08
guerd87
Just call me: John, Still trying to earn a #
 
Pakenham, VIC
Australia
I find that ebay and such are pretty expensive for what you get in old PC's, Im a long time member of the www.overclockers.com.au forum from way back when I use to be into PC's alot. They have a great for sale forum (need to be a member for more then 3 months to view it, so sign up now )

I just picked up my CAD/CAM/Controller PC from there. AMD 2800+ 64bit, 2GB Ram, 2 x 500GB HDD's, Radeon 9800 Pro - All for $20 pickup 10 mins from my place

The forums are good to buy cheap stuff from, but not so good for selling stuff on. You wont get a good price for your stuff, but it usually sells in a couple of hours or so if its decent

Ive ordered my electronics this week, $660 delivered for 4 x motors and controllers
Reply With Quote
  #26  
Old Mon 26 July 2010, 07:48
Red_boards
Just call me: Red #91
 
Melbourne
Australia
John,
Good to hear its progressing.

I received motors today. Well packaged and delivered UPS from China. I'm very happy with the service I got from Mr Media Lee at Motionking.

Mach3 software installed... now to that kitchen table project...

Last edited by Red_boards; Mon 26 July 2010 at 07:49.. Reason: spelling corrections!
Reply With Quote
  #27  
Old Tue 27 July 2010, 07:32
Red_boards
Just call me: Red #91
 
Melbourne
Australia
24 or 36 teeth?

Rack and pinion question

OK, after a bit of reading I understand "if you want max speed with slightly lower cut quality, use 36 teeth module 1. If you want slightly lower speed and better cut quality, use 24 teeth module 1" [Gerald]

But then there's the issue of power delivered to the motors:

My 60V supply will give more torque but less speed (over a 40V supply, say)

So my logic is to go for 36 teeth initially because I'm starting out with ungeared motors and am looking to trade off between the speed of the 36 and the torque of the 60v.

What do you think?

I realise that this is not a make or break decision, but it will help me understand setting up Mach3.
Reply With Quote
  #28  
Old Tue 27 July 2010, 10:48
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
For ungeared motors, the drive pinion gear must be as small as possible. (It is only the folk with geared motors that can play around a bit with the pinion gear sizes)
Reply With Quote
  #29  
Old Tue 27 July 2010, 13:37
Kobus_Joubert
Just call me: Kobus #6
 
Riversdale Western Cape
South Africa
Send a message via Yahoo to Kobus_Joubert Send a message via Skype™ to Kobus_Joubert
When I did my machine I read something about 20 tooth pinions. So I went and bought 20 tooth pinions. They were so small I had to make a sleeve to strengthen the part that fit on the shaft of the motor. Later I found out that 24 - 27 tooth metric are the ones I should have bought.
But for more than 2 years of use, those little 20 tooth pinions are doing the work connected to the MotionKing steppers.

Maybe that is why I am happy with my cut quality without gearboxes.
Reply With Quote
  #30  
Old Tue 27 July 2010, 22:42
Red_boards
Just call me: Red #91
 
Melbourne
Australia
Thanks Gerald and Kobus for the definite responses.
24 teeth it is. I can always shed voltage.
Reply With Quote
Reply

Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Making Skins #74 - Brisbane Australia Surfcnc MechMates already cutting 1078 Sun 20 September 2015 12:05
A chip off the old block quadtech Miscellaneous / General / Whatever / Catchall 0 Tue 23 August 2011 08:30
Anyone need more bearings? MELBOURNE rotorzoomer The Market Place 1 Fri 12 February 2010 07:45
M1 18 000 Alternative Stopper Block dmoore 20. Gantry 15 Fri 13 June 2008 13:47
Rail and Block John Archives 2 Mon 09 April 2007 16:25


All times are GMT -6. The time now is 07:25.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.