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rmtucker
08-02-2003, 08:40 PM
hi guys

just thought i would post some piccys of my attempts so far.
Table size is approx 1250mm*770mm*350mm
any comments would be thankfully recieved.

Mark

cncadmin
08-02-2003, 09:38 PM
WOW. great job looks very solid, what are you using for a router motor?

Rekd
08-02-2003, 10:01 PM
Nice Job!

'R3kd

cadcam
08-02-2003, 10:47 PM
I have to say vary nice job so far.
That looks as nice as some of the routers I saw at the show today.

CAMmando
08-03-2003, 12:48 AM
Looks really solid.

What do you intend to be cutting with it ?

kong
08-03-2003, 06:30 AM
*/kong repeats what everyone else has said/*
Just wanted to subscribe to the thread so I get the updates!:rainfro:

rmtucker
08-03-2003, 06:41 AM
Ok

Here is another view of y axis
Have not made my mind up what to use as router head,prob just a standard router as there is not much to choose from here in the uk.Only set back to this is the noise and duty cycle on the bearings.as for what i will cut "not sure yet" depend how the 4th and 5th axis works out.Always fancied sundials and congreve clocks as a starting place.I will post more photo's if required and also updates when x axis leadscrews are fitted and energy chains etc.
thanx for the positive replies,i need as much encouragement as i can get as building from scratch is a long job!!.

Mark

tsalaf
08-03-2003, 10:57 AM
Thatís REALLY impressive for a first machine. Please keep us updated.

As for routers, my personal experience is that high quality routers like Makita will last for many years with continues use without needing bearing replacement.

Steve

www.tac-pro.com.

jimini
08-03-2003, 12:30 PM
Really a superb job keep the pics coming.........

HomeCNC
08-03-2003, 09:26 PM
Nice aluminum work!

abasir
08-03-2003, 10:32 PM
Hi Mark,

Looks really nice & solid. If you're next door to me, I probably beg you to sell it to me. Keep us updated, pleeease.

JIMMY
08-03-2003, 11:46 PM
Very nice design. I am very inpressed. I am designing my router right now and I have been trying to come up with some ideas how to get the router to be in the center of the gantry. Your idea is such a easy fix to that problem. Very nice machine.

balsaman
08-04-2003, 05:14 PM
Yup, looks great!

Eric

bunalmis
08-05-2003, 03:20 AM
Hello rmtucker

Very nice and strong machine. Axis weight seems very heavy.
What is the axis speeds?

rmtucker
08-05-2003, 04:54 AM
Not sure on axis weight but i have had the axis running at:-
14,000 mm/min = 550 in/min
but i would not run them at this all the time
the intended design speed was 4000 mm/min(160in/min)

Mark

rmtucker
08-05-2003, 02:04 PM
Ok people

I added the X axis leadscrews today.I have not added the metalwork that runs under table yet that drives the axis yet but here is piccy of configuration.

Mark

ccm
08-07-2003, 02:48 PM
That is one impressive machine !! Very good design, I like the single motor drive for the two leadscrews... great idea.
Other than obviously a mig to make up the frame of the unit, did you just utilize a bending brake for most of the formed aluminum pieces ? Or did you have them made somewhere ? best looking homebuilt I've seen yet, good job!! Rivals production units and probably is of even better quality because you payed attention to every last detail.......

- my hat is off to you!!!
let us know how she works..

arthur

mwestern
08-08-2003, 12:50 AM
hey rmtucker,

Nice machine, I was wondering where you aquired your belts and pulleys shown in the last pic.

Mark

cncadmin
08-08-2003, 01:02 AM
This is gonna be on BIG thread!!:0 I really like your design keep the pic's coming, great job!

rmtucker
08-09-2003, 09:59 AM
Hi guys

Slow work at the moment doing all those niggly bits.
Got the control box and made the heatsink (long job!!!).
In reply to an earlier question all the parts have been made from scratch by myself using my works machinery.
Here's a piccy of the heatsink,it's so BIG i can hardly fit it into the photo???.

rmtucker
08-09-2003, 10:01 AM
Well slow going in this area but should be able to drive the x axis at the beginning of next week.Just adding carriage to drive the x axis just the nut holders to make.

rmtucker
09-27-2003, 02:49 PM
Hi all

Been a little busy lately so have not been able to update you much on progress.Well all was going well till this afternoon when testing the z axis,When BANG!!!! the motor cable got caught in the z axis and sheared right through it.Result was one blown Gecko 210 (Bollocks!!!!!).Short of getting on my hands and knees to my wife for another £150.0 thing will be on hold for a while.
Well i suppose i'll have plenty of time to post some piccy's and updates now.

Mark

Marc Soren
09-27-2003, 10:38 PM
Mark
This Marc would be happy to help get another gecko for you.
They run about 89 quid instead of 150 you mentioned. (I don't have a pound key!)
I am not a dealer & I'm sure others would help as well. I used to send audio circuits to a bloke north of London and it worked rather well. All on the up and up.

We appreciate the high quality pictures you send. Very posh.
Can't wait to see the next installment.

Marc and the boyz

ger21
09-28-2003, 10:33 AM
You can probably get it repaired by Gecko for a lot less than replacing it.

Gerry

Cameron
09-28-2003, 01:08 PM
Very nice table. If you donít mind me asking, how much has this cost you to date?

balsaman
09-28-2003, 02:01 PM
I would contact Geckodrive and see what they say about getting it repaired. They are very good about these things.

Eric

Marc Soren
09-28-2003, 03:08 PM
Mark

What are the specs on your lead screws and the nuts?

Marc

rmtucker
09-28-2003, 09:41 PM
Hi all

I have already been in touch with marris at geckodrive and he has offered to repair the busted 210 if it is repairable free of charge.If not he has offered to replace the sorry item free of charge if i give him an explanation and the heart wrenching details of how it happened, Marris has a large heart when it comes to poor machine builders like myself.
Many thanks Marris !!

As for the cost to date,i'm not exactly sure but i would reckon about £1500.00 when all 5 geckos are fitted.

The leadscrews are just 16mm*4mm pitch rolled trapezoidal form,and the nuts are matching phospher bronze which i have modified for anti backlash adjustment,this enables me adjust backlash in .01 mm steps.I will over the next few days post some photos of my progress and more detailed photographs of antibacklash adjusters and the new control (minus the blown gecko) and the limit and ref switches that i'm on fitting to the z axis.

Mark

balsaman
09-28-2003, 10:29 PM
I too ruined a drive which Geckodrive repaired for free. They go above and beyond IMHO.

Eric

cbcnc
09-29-2003, 04:35 AM
Mark,

Sorry to hear of your woes. You have a nice looking machine that appears to be excellently engineered and built.
I would be interested in seeing how you are mounting your limit and home switches as I am doing the same thing on my machine. I seem to have alot of questions on how to do it without problems. But that is the last thing for me to do before I'm running it.:D

Chris

rmtucker
10-17-2003, 09:23 PM
Well

After some initial problems with the z axis and the blown Gecko,things are starting to move again.The z axis was just not physicaly strong enough or straight enough using the configuration shown in the attatched photo.So i completely stripped the axis down and rebuilt with the following changes.

1. The 16mm linear rails are now bolted along their length on to a u channel which runs up the centre and the closed linear bearings have been changed to the open type.This has effectively made the axis stronger by 10 fold.when squaring the axis up i now only get a .02mm error from top to bottom in both directions which even if i do say so is not bad for a machine completely made from scratch except for the linear bearings.

2. Have added an extra microswitch for a seperate homing.which means that homing and limits are now seperate.

3.In process of adding the switchbox for router supply and cmm probe connection.Which the energy chain for the z axis will also fasten to.

I will post a picture in the morning of the z axis with the above changes to clarify what i have done.

Hardway
10-18-2003, 01:38 PM
This is an awesum project.
I would like to do the same. and I will be reading
these posts for more info on the electronics parts of the design, because thats the area that I know little about.

Scott Bond

rmtucker
10-18-2003, 03:30 PM
Here we go!!!

Here is the next instalment as promised.Please if Admin Gets sick of my bombardment of photographs just shout stop.
First photo is of the z axis mod i talked about last night.

rmtucker
10-18-2003, 03:34 PM
Next Picture is of z axis guarding.

rmtucker
10-18-2003, 03:35 PM
Z axis guards and y axis guards

rmtucker
10-18-2003, 03:39 PM
I had to modify these switches as follows.The older photographs of these only showed 2 switches for shared limits and reference.But after more info i decided to seperate the ref and limits so a 3rd switch was added to the bottom.Sorry about the quality of this photo but i,m lying on the machine for this one.

rmtucker
10-18-2003, 03:45 PM
This one is only part filled with geckos but all the wires and clamps are in ready to take them.The white patch you see on the left is the missing Gecko that i 'buggered'.Marris has just informed me that it should be on its way back fully repaired free of charge.I can not thank Marris Freemanis enough for his help on this one and would recommend Gecko's to anybody as there after sales service is second to none.If you take note that there is spaces for 5 axis in the box,So i have a long haul yet.Power supply is 70v @ 22 amps which should drive the 5 Gecko's without a problem.

Mark

Is everybody sick of my photo Bombardment yet ????????

balsaman
10-18-2003, 04:07 PM
Nice unit. You have a machine shop in that garage somewhere??

:)

Eric

kong
10-18-2003, 05:10 PM
What Balsaman said! The quality of craftsmanship on your machine is astounding.:eek:

rmtucker
10-18-2003, 07:01 PM
Hi Guys

No Machine shop at home,But shhhh!!! I work permanent nights in a cnc machine shop.Thanks for the encouragement guys i think this project may just get completed.unlike some others i have done over the years.Teee Heeee!

I am fitting the energy chains for the cabling over the next few days to prevent an occurance of the earlier unfortunate accident with the gecko.Bit like bolting the stable door after the horse has bolted but let this be a lesson to others,Untidy wiring and practices usually lets the smoke out of something.

Mark

dcd121
10-18-2003, 08:22 PM
Beautiful work. I think your chip sweeper status is due for an upgrade

NeoMiller
10-19-2003, 04:37 AM
Can you please let us know the source of lead screws. Or tell us more about these. Thnx

rmtucker
10-19-2003, 10:22 AM
Hi guys

The Leadscrews are just toughened rolled trapazoidal form,16mm dia * 4mm pitch.The nuts are phospher bronze matching the leadscrews.The nuts have been split and inserted into a steel sleeve screwed at both ends with a 1mm pitch thread,i have then added 80 serrations around the o/d of the flange on the nut.A small screw with a point on it locates in the serrations and this enables me to take any backlash up on the nut in very small increments (.0005").The leadscrews and nuts were just stock items from Ondrives Ltd here in the UK.

Mark

bb99
10-19-2003, 03:01 PM
HI All, I'm new to the concept of CNC machining. I've got a simple question. What exactly is backlash? I can think of several possible definitions, but I'd like to know for sure.

Thanks,
bb99

ehiebert
10-19-2003, 05:25 PM
Backlash is freeplay in a mechanical mechanism. With leadscrews its the freeplay in the nuts of the leadscrews. You can feel this on a simple bolt/nut combo.

Take a bolt and a nut and screw them together so that the nut is fulley engaged on the thread, but not tight against anything like the shoulder of the bolt, etc. Now try to pull/push the nut. You will feel some freeplay in the nut... and the measure of freeplay is the measure of backlash.

Put another way, if you turn the nut clockwise it will engage the bolt and wind up the shaft, but if you now try to reverse the nut you will have to turn it about 1/4 to 1/2 a turn before the nut engages the thread in the reverse direction. That is the measure of backlash in terms of turns on the screw.

Is that understandable?

bb99
10-19-2003, 07:27 PM
ehiebert


Perfectly! I had two other potential definitions in my mind and wasn't sure which was correct. Also, thanks for putting it in terms of screw turns. That was quite helpful!

--bb99

balsaman
10-19-2003, 08:39 PM
backlash is also found in the lead screw support bearings. When this happens the whole screw can move back and forth a little. This is where most of the backlash is presently found on my machine.

Eric

rmtucker
10-29-2003, 03:11 PM
Well

The time is here to decide on a breakout board or not.The problem is in the uk that there are no breakout boards available, so it,s either make one or do without.Anyway here is a new piccy of the completed z axis.The router is now mounted and all the guarding/ energy chains in place.I have just ordered the energy chain for the y axis and i will finish the limits and ref wiring on the y axis this week.Not Long now !!!!!!!!

Mark

Mr.Chips
10-29-2003, 10:00 PM
Mark
Do you have a web site with additional photos of your good lookin machine? If not could you post some picture of your Y and Z axis?
Thanks
Hager

Mr.Chips
10-29-2003, 11:58 PM
Sorry Mark,
I found them on page 2 of this thread.
Hager

gloomyandy
11-18-2003, 07:38 PM
Hi Mark,
Nice looking machine! Where abouts in the UK are you based? I'm in Leeds myself! What are you using as the router on your machine? My own setup is a little less professional than yours (I'm really using it do help me develop my interest in the control hardware/software). Isn't it a little frustrating reading posts from the US guys both the prices they have and availability....

Andy

rmtucker
11-19-2003, 02:33 PM
Hi Andy

I live in Co Durham,At this point i have bought just a cheap 550w router which will still give me somewhere to start and when it wears out i can just throw it away.As for American parts availability and prices, i tend to find that prices are not too bad here but parts take a lot more searching out.But on saying that,It still makes me green with envy at the choice these guys have.Just a footnote about the machine,All is well and i will be posting some updated photo's shortly.I have been busy with the tidying up of cables and gaurding,because i fear if i wait until the router is fully working it will never get finished.(like most projects).
I have also added a renishaw cmm probe for probing of surfaces i will try and post some photo's of this also.
Very nice to hear of somebody else in the uk though!!!

Mark

mysterious
11-19-2003, 05:02 PM
All I can say is great work.

snokid
11-22-2003, 10:17 PM
truely inspiring!!!

now to get off my butt!!!

Bob

Bloy2004
11-23-2003, 01:29 AM
You are setting new standards for construction design and craftsmanship! If my project can be half as good...I'd be happy.

umrk
11-23-2003, 02:20 AM
I am impressed!

mike
(not easily impressed)

rmtucker
11-26-2003, 11:38 AM
Hi Guys

Just a piccy of the energy chians in situ,Still got some of wires to route through them.I am trying to tie all the loose ends up because if i wait until it's running 100% they will not get done.

Mark

rmtucker
11-26-2003, 11:42 AM
Oh while i'm on

I have also fitted and tested the cmm probe,Guess what it works 100%.A strange feeling when you see this machine thundering about at 4000mm/min and you put your hand under the probe and it stops with such little force on the probe.

cncadmin
11-26-2003, 12:35 PM
That is one sweet machine. :)

kong
11-26-2003, 12:55 PM
Please excuse my ignorance, but what is a cmm probe?! Some sort of touch probe I know, but are you using it to set up the machine, or will it be used for 3d scanning?

rmtucker
11-26-2003, 02:19 PM
kong

It's a renishaw touch probe,It can be used for measuring or scanning.In my case mainly scanning (copying i hope).Not quite sure what i will do with the machine till i try cutting but mainly signs and clocks,sundials in fact anything i can fit in.I will be looking at 4th and 5th axis soon,while i'm waiting of x axis gecko and motor.

Mark

ps all comments are appreciated as this is what keeps the project going.

Boros
11-27-2003, 05:07 PM
I must say that the router is most impressive.

My question is to do with the renishaw probe.
What model is it?
Are you using the renishaw interface?

I have several probes awaiting my router to be completed.
I plan on having my probe retractable so I can use it for both digitising and measuring offsets.
I also plan to have another probe for Z hight measurment.

Thanx

Boros

jimini
11-27-2003, 08:05 PM
What is the total cost of the probe and interface if you don't mind?
And what software would you use with it?

rmtucker
11-28-2003, 03:05 AM
Hi Guys

The probe is a Renishaw LP2,Which i believe is one of the old machine probes.I'm afraid it did not cost anything as i procured it from a box of disused tools at work.I only plan on using Mach2 for the router which has all the capability i need as far as the probe is concerned.Anything that is not in Mach2 can be written into the Macro facility.Oh also the probe is wired directly to the parallel port as no interface is required with the LP2.
Hope this helps !!!!

Mark

georgebarr
11-28-2003, 04:47 PM
How will your Z-axis motor mount? Normally, I have seen the motors mount on the top side of the z-axis. But since you have the z-axis installed differently, the motors direction would have to be reversed (I think!). I too plan to install a Z-axis just like you have in the picture. I would like to know how the motors will mount so that I can help solve my cnc setup.
Thanks,

rmtucker
11-28-2003, 07:36 PM
George

If you look at recent photo's the motor is already mounted but hidden by the switchbox.

See:- http://www.cnczone.com/attachment.php?s=&postid=16112

Mark

rmtucker
11-30-2003, 07:53 PM
Hi guys

Just a quick message to let you know i am setting a web page up
for Photo's and Video's and some history of the machine.Reasons for this is that the limits on cnczone only allow small pictures and no video.I will continue to post on this site as well as my webpage just that there will be more detail on the web page.The site is still under construction so bear with me.

http://website.lineone.net/~rmtucker/

Have fun!!!!!!

Mark

JIMMY
12-02-2003, 12:24 AM
very nice router mark

cncadmin
12-02-2003, 12:35 AM
Originally posted by rmtucker
Hi guys

Just a quick message to let you know i am setting a web page up
for Photo's and Video's and some history of the machine.Reasons for this is that the limits on cnczone only allow small pictures and no video.I will continue to post on this site as well as my webpage just that there will be more detail on the web page.The site is still under construction so bear with me.

http://website.lineone.net/~rmtucker/

Have fun!!!!!!

Mark

You can post vids just zip it, did you try posting your pics in the photo gallery??
http://cnczone.com/photopost/index.php

rmtucker
12-17-2003, 11:29 AM
Does anybody know where i can get a suitable table top for this baby,here in the uk?.I was going to use some 1/2" aluminium plate, but this is proving difficult to get hold of.And i can not find anybody that is selling any kind of t-slot table at all.
The table top is around 1250mm * 770mm,so wood would not really an alternitive (not accurate enough).Any pointers would be appreciated as at the moment any jobs would fall down the middle.

Mark

http://website.lineone.net/~rmtucker/

buckie555
12-17-2003, 12:05 PM
Mark

I'm in the process of building a similar sized router to yourself. We used 15mm thick 5083 1440mm*720mm Aluminium plate for the machining surface. The bending plate calcs yielded a max deformation of about 10microns under a 50kg load - that was good enough for us. I bought it for about £120 from Metalfast ( I believe the website is www.metalfast.com but do a search on google if not), they've got a few branches around the UK and are very helpful. I've ordered quite a lot of plate and angle from them for the machine I'm making and everything they've supplied has been top notch.

Neil

kong
12-17-2003, 02:22 PM
If you are prepared to drive to Southampton there is a scrap yard on Portsmouth road that can yield some good quality ali for £2 a kilo. It is what I used in my router.
Alternatively, you could go half wood half ali, which is what I intend to do with mine. 18mm marine ply base, with 6mm ali plate bolted on top. Depends how well it's supported though I guess.

xairflyer
12-17-2003, 03:51 PM
I have got alloy plate before from Amari/Aalco stockist without any problems.

Also you could try 25mm or 32mm MDF for the base, I am using 25mm on mine. 900 x 850

rmtucker
01-01-2004, 07:15 AM
Hi ppl

I was wondering if anybody could shine some light on this subject?.
Due to the fact that Alzanti UK is no longer stocking Gecko 210's,I am going to have to buy the 3rd Gecko direct from Marris at Geckodrive.
I have never imported anything in the past so what is the procedure and cost in the UK?.
I know the item itself is $148.00 and Vat will apply but what is the import tax on an item like this?.
I have heard it can be 0-80% of the items cost,And how is this payable (At the door on delivery?).Also how long does it take in customs.I know this is off topic but i know a lot of ppl out there that are reluctant to buy from usa because of these questions.
any help would be appreciated on this matter because i am hoping to order before next week.

Thanks
Mark

http://website.lineone.net/~rmtucker/

kong
01-01-2004, 07:22 AM
All bought my gecko 320's from the geckodrive website, and the service was remarkable. I had several emails letting me know they were despatched, etc. Delivery was about 3-4 days, and cost about, erm, $40 (bit of a guess, sorry). As for VAT, I got caught. The delivery guy wanted £60 on the door. As I never had it, he returned the items to the depot, and I had to phone them and pay by credit card. As you are only buying one, you may get away without the VAT. I have imported loads of stuff, sometimes you pay, sometimes you get away with it if the value is low enough.

rmtucker
01-12-2004, 06:11 AM
Well i did it?

I recieved the last Gecko and motor over the weekend.
I decided to lower the machine on to its wheels to turn it round while fitting the remaining limit switches etc,BIG MISTAKE !!!!!!!.
The gantry was not fastened and guess what , it rolled off the end of the table and went crashing to the floor.Approx 250 lbs of hard work missed my head by about an inch.It put a gouge in the concrete floor about an inch deep,ripped all the wires out of the motor connection boxes,obliterated the digitizer socket.And worst of all me and my son who stands over 6ft tall could not pick it up off the floor.The whole gantry had to be stripped on the spot and checked for damage etc,then placed back on the machine and rebuilt.
Anyway the machine is back on track and should be finished in the next 7 -14 days.I think the moral of this story is never never never lose site of the safety aspect of these machines,even though they are home made they are just as dangerous as their big brothers.If it had hit me when it came off i would have needed an undertaker not a paramedic.!!!!
I will post some photographs of the final build in the next few days,And then on to the best bit putting a cut on after nearly 2 years work.Hoping to arrange some video of this.

Mark

http://website.lineone.net/~rmtucker/

bb99
01-12-2004, 12:47 PM
Sorry to hear about the crash. How bad is the damage to the gantry?

--bb99

anoel
01-12-2004, 12:53 PM
Ouch.... Better Bolt a couple of stop plates at the ends of the rails to prevent this from happening again...

rmtucker
01-19-2004, 05:36 PM
My First cut

Mark

rmtucker
01-19-2004, 05:37 PM
My Second cut

mark

Cold Fusion
01-19-2004, 05:49 PM
Great looking machine and great looking cuts.

Hobbiest
01-19-2004, 06:12 PM
Awesome! Nothing else to say...awesome.

Mr.Chips
01-19-2004, 06:30 PM
Good job.
This is what it's all about.
Hager

cbcnc
01-20-2004, 02:13 AM
Mark,

That is a fine looking machine! It's an inspiration for us all. Congratualations!
Of course now you will have to live up to what it's capable of. Please post further pictures of your work for us to see.

Chris Barker

kong
01-20-2004, 04:33 AM
Good work! nice to see it has all come together for you.
What did you do about the table-top in the end?

rmtucker
01-20-2004, 06:34 AM
Kong

Table top has just arrived from Metalfast this morning.
Thanks for the info my friend.

Mark

Carver
01-20-2004, 10:52 PM
Mark, Know you get tired of hearing what a fantastic job you've done, But you have kept many of us sitting on the sidelines smiling fiercly for some time.

Congrats on a really cool machine and on your attitude retention after the crash. I have some commercially produced routers that can only wish they had your attention to detail.

Keep us up on your advances in cutting and the new axis progress.

Best of days, and thanks for sharing,

Phill Pittman
www.masterwerkes.com
digicarve@verizon.net

rmtucker
01-25-2004, 08:33 PM
Hi guys

Well i have spent about a week trying to tune the motors in but i am still losing steps.Can not tell if it is mechanical or the electronics but i tend to sway towards the electronics.It seems like a very gray area this,How to wire the inside of your controller.The reason i feel it's electronic is that it does not matter what i set acc/vel to in mach2 i am still losing steps.Or am i just expecting too much.Any advice that anybody could give me at this point would be much appreciated because right now i got £2000 of scrap metal.Can you tell i'm pulling my hair out?.

Mark

balsaman
01-25-2004, 08:43 PM
It's very important that your step/direction signal cables are shielded, especially inside the controller box. The shield ground on my cable inside my controller came off and I had all kinds of trouble.

Eric

rmtucker
01-25-2004, 08:48 PM
hey balsaman

is there any pics of your control,maybe i will be able to see where i have gone wrong?

mark

balsaman
01-25-2004, 09:30 PM
Yeah, it's not going to help you much tho. Too full.

Eric

balsaman
01-25-2004, 09:34 PM
The cable from the breakout board (little board right in the middle) to the geckodrives (on the door) is the one that the shield wasn't grounded.

Also make sure you set the software to "active low" on the step pin for the geckodrives. Otherwise you loose one step each new gcode move for that axis.

Eric

rmtucker
01-25-2004, 09:37 PM
balsaman

should the dir pin also be active low ?

mark

balsaman
01-25-2004, 09:47 PM
Dir doesn't matter, as it only changes when the direction changes, and doesn't affect the steps. Changing it to active low should change the axis direction.

daytrader
02-01-2004, 10:36 PM
Great looking machine.

What is its repeatability in a small area, such as 2 in square? I'm looking to build a machine to do inlay work in pool cues, which I think would require a repeatability of .001in (within a small area). *Edit* If you were able to measure this with your loss of step problem.

How did you ensure the linear rails were parallel in both directions? How flat was the surface you mounted the linear rails to? Did that surface irregularity transfer to the rails? Did you level the machine before adjusting any of the rails?

Why did you decide to use two leadscrews to move the gantry? Before the leadscrews were attached, did you notice any racking of the gantry, which would dictate the use of two screws? Do the screws seem to rotate simultaneously, or do you think one may start to rotate before the other, contributing to some racking of the gantry?

Thanks for the inspiration.

turmite
02-02-2004, 02:06 AM
Mark do you frequent the Mach2 user board over on Yahoo? Seems like a good bunch like here but I hate the Yahoo format.
There has been a long thread about some lost steps in one version of the Mach2 releases and you might want to check which release it is.

BTW when I sw your first cutting pic I though you had taked the kitchen table and engraved it a little!!:D

Mike

rmtucker
02-02-2004, 10:01 AM
Hi guys

I am afraid i have neglected everybody and everything over the last 2 weeks.I had got the machine up to the final stages of building and hit some major software problems.So i am afraid the remaining metalwork and hardware has come to a standstill.The software problems involved lost steps and constant velocity in Mach2,And has still not been resolved.The trouble is that there are no other pieces of software out there offering constant velocity at such a small price.So it is a matter of hanging on to see if we can resolve this matter.

As far as repeatability is concerned (excluding lost steps),It is repeating to within .01mm which is all that can be measured with a standard clock.Gantry racking is something i thought of in the design stage and is really reliant on the type of application and width of table.In my instance the gantry is about 800mm long which would cause a problem when taking heavy cuts so i went for 2 leadscrews and they work perfectly and in tandem.Getting the linear rails parallel was not a problem beacaus the frame work they are built on is parallel to .001".Squarenes is something that can be adjusted by adjusting the twin leadscrews etc.

As far as the thread on mach2 is concerned (it is me!).

Regards
Mark

turmite
02-02-2004, 11:29 AM
Hey Mark I have been reading the thread over on Mach2 and you guys are way too deep in for me anyway. I will say though that I believe Art will get it fixed. I am curious, and not having read every post on this thread here, are you running servos or steppers? The reason I ask is I am running in cv also and was wanting to know how you will know if you have lost steps if there is no absolute linear feedback. I posted a question down on the electronic's forum here and so far balsaman is the only one that has replied the post but still not to my satisfaction.

I'll ask you and if you want you can have the mods to delete this.

If a machine runs servos without linear scales for a closed loop feedback system, isn't it just like a open loop stepper system except more powerful?? Which brings me back to my question, how cal you tell if you are losing steps?? I have a need to know!:D

Mike

rmtucker
02-02-2004, 11:40 AM
Turmite

Measuring lost steps is easy.Mark either the pulley on the motor shaft or leadscrew and mark an adjacent point on the framework.
Set the machine to "0" and run your program which at the end should go back to 0,0,0.If the marks line up again then you aint lost steps.I find in exact stop mode i can tune the motors to any settings i like and the machine will return to 0,0,0 but if i run a program in cv mode ie 3d machining it loses lots of steps.
I am using steppers and gecko 210's

Regards
Mark

turmite
02-02-2004, 02:10 PM
I am using steppers with the 201's but have not checked for lost steps like that. I did do it with a dial indicator but not on very long moves. I think I will do that this afternoon before I run my program I was just about to run. What rapids and moves are you running, as well as which version of Mach2. I am still using release 1.90 and will not move up till the problems are solved and the program has been stable for a while. I am just now getting back to work full time because this retrofit was not as simple a deal as I though it would be, but then again I also install a 4th axis this time and that has been a bear. Let us know how things go.

Mike

rmtucker
02-14-2004, 08:27 PM
hi guys

Just lookin for some second opinions here concerning accel and vel of motors.Most of you guys have seen my machine and motors etc.

If not here we go:-
Nema 34 - 720oz 2.7v @ 4amps
4mm pitch leadscrews
2:1 gearing on x axis
1:1 on y and z
Gantry at a guess is about 120-150kg
Gecko210 drivers
x set to 5 microstep
y and z set to 10 microstep
70v @ 22amps powersupply


I am currently getting a max vel of 60.0mm/sec and accel of 73mm/sec.


Do these figures sound ok or not?.What should i get if these are wrong.
Could you guys give me some idea what rates you are achieving in vel and acc?,and a brief desc of your set up.
But only if you know and have checked that you don,t have lost steps.
Any input on this would be much appreciated.

It seems to be a bit of a black art setting the acc and vel.

Regards
Mark

balsaman
02-15-2004, 12:19 AM
It varies a lot from machine to machine. Go as high as you can until you loose steps, then reduce by 20%.

E

arvidb
02-16-2004, 06:30 AM
Let's throw some numbers at it, just for fun :)

Gantry mass = 150 kg
Lead screw pitch = s = 0.004 m/rev trapezoidal with bronze nut, typically 30% efficient (Eff = 0.3)
Stepper holding torque = 720 oz-in or about 5 Nm
Linear ball bushing guides, coefficient of friction, u, about 0.01?
Acceleration = 0.073 m/s^2
Top Speed = 0.060 m/s

Speed of 0.06 m/s with lead 0.004 m/rev => screw has to turn 15 rev/s = 900 RPM.

To accelerate 150 kg at 0.073 m/s^2 you'd need about 11 N of force (F [N] = m [kg] * a [m/s^2]).

The frictional force of the gantry would be 1.5 N (F [N] = m [kg] * u [dimensionless]).

So the total force needed to overcome friction and accelerate = 12.5 N. You could try if this is anywhere near correct by hanging a 1.25 kg weight from a string pulled over a pulley and fastened to the gantry, and see if it accelerates approximately like it does under power when you release the weight. It would be interesting :) It would require that the rails are perfectly horisontal to get a valid measurement, though.

The torque required to turn the screw(s): M [Nm] = F [N] * s [m] / (2*pi*Eff) = about 0.027 Nm. Add to this frictional torque of the screws, maybe 0.02 Nm * 2 screws and we get 0.067 Nm. Because of the reduction of 2:1 we have to divide this by two, so we get 0.034 Nm. And then the efficiency of the timing belts, perhaps 0.85 => 0.04 Nm (or about 5.7 oz-in) @ 1800 RPM.

This sounds low, perhaps I've forgotten something? But remember this is the force to only accelerate the gantry and overcome friction, no cutting force included. I guess the RPM is pretty high for a stepper, so maybe it's close to its top speed, with not much torque left? This would coincide nicely with this being the top rapid (no-cutting) speed for this machine.

Comments, please :)

Arvid

arvidb
02-16-2004, 06:53 AM
As a site note, any tilt of the gantry guides from horisontal would cause a significant amount of "lifting" force to be needed to move the gantry.

The force of gravity ("weight") of the gantry is 150 kg * 9.81 m/s^2 = 1472 N. 1 degree tilt would add sin(1) * 1472 N = 25.7 N of lifting force to be needed. If not held in place, this force would cause the gantry to accelerate at (25.7 - frictional force of 1.5 N) / 150 kg = 0.16 m/s^2. I guess you noticed this when you tried to move the machine around before :)

(g = 9.81 m/s^2 is the gravitational acceleration on the surface of the earth. Actually it's 9.82 m/s^2 here in Sweden since we are close to the pole, and the earth is a bit "squashed" - so we're closer to the centre of the globe here :))

Arvid

rmtucker
04-11-2004, 10:06 PM
Hi guys

Sorry about the delay with the next installment but the last few bits have been a little tricky.I have fitted the table top and fly cut as much as i could reach (1" band was unreachable at the rear of table),This did not matter too much as the guards will be in this area.The table is flat to within .0005" with a clock and renishaw probe.I have drilled a matrix of 8mm tapped blind holes for clamping purposes.The guards are unfinished in this pic but should be finished this week.

Mark

rmtucker
04-11-2004, 10:10 PM
Well guys

Here is the finished control (just 3 axis at this point but wiring etc is in place for all 5 axis).The biggest change you will be able to see at this point is the removal of nearly all logic wiring from the controller and the addition of an ssr to control the spindle.I will show the location of all logic wiring in a following post.The main reason for the move was to make sure that there were no interference problems etc.

Mark

rmtucker
04-11-2004, 10:13 PM
Here is the piccy of the logic box or breakout box as promised.This arrangement made the wiring much simpler and also seperated all the high voltages from the logic etc.
It also meant that the parallel cable could be much shorter.

Mark

rmtucker
04-11-2004, 10:16 PM
I have also added Guarding to the front and r/h end of the machine to prevent any unwanted amputations which also acted as a shield between the logic and motors etc.

Mark

rmtucker
04-11-2004, 10:20 PM
As can be seen from the attatched photograph i have added a renishaw lp2 probe for scanning etc.
This works a real treat.
You can also see the beginnings of a Auto tool setter made from a renishaw mp3 Machine probe,which i will fasten to the corner of the table and it will allow me to press a tool set button in mach2 and auto set tool lengths.

Mark

Zagroseckt
04-13-2004, 06:21 AM
amana amana amna want your addy so i can come and steel that one from ya... J/K

MAN that thing looks like it belongs in a clean room in some multimilliondoller shop...

WHOLLLY!
How the heck did you Build that!

You could probly sell that thing for 20grand or more... it just looks SWEET!
You had to of had some of that CNCed to begin with....

How much did all that cost you!
I'm just blown away!
Totaly blown AWAY!

rmtucker
04-13-2004, 02:26 PM
Well

I tried it tonight and guess what it works.
15mins each.
Gonna try and finish machine tho before cutting anymore.

Mark

kong
04-13-2004, 02:37 PM
Nice work, nuff said!:wave:

Ali Kat
04-13-2004, 06:50 PM
You have obviously worked long and hard to produce such a fine piece of equipment so now youíve earned a rest.
If you can give me your full address and some idea when thereís nobody home I'll come and steal it so that you can go fishing or something!!!! (Durham's only an hour or so from me!)
Seriously though, I am well impressed with the construction and effort that you've put in. I am in the early stages of constructing a cnc router and can only hope that it works 50% as well as yours.
You mentioned in an earlier posting that the linear slides and bearngs were "cheap". How cheap and where from is the question as the RS catalogue makes me go pale when I see the £££.
keep posting those pics, if not for anyone else it keeps me from dropping off infront of the telly!
Regards
Ali Kat

rmtucker
04-14-2004, 02:38 AM
The linear berings were approx £8.00 ea and the linear shafting was about £10.00 per metre.Don't use R.s. for anything like these items try your local bearing stockist.The linear shafting is pre hardened to 62 rockwell so you may have trouble drilling it as the hardness is approx 2mm deep.I used high speed depo cutters designed for cutting armour plating.I know you can buy the shafting pre-drilled but this will bump the cost up.

Mark

rmtucker
04-25-2004, 05:38 PM
Well i am still busy cutting widgets as somebody on this board called them,(To keep the wife happy!!!!).Maybe be able to get some serious work done shortly.

Mark

trubleshtr
04-25-2004, 06:40 PM
Hi nice unit!
I have been following along and would like to know if you have any pics of the nuts that you modified, I read your description, but I am a very visual learner and would love to see how you achieved the anti-backlash aspect of the nuts.

Many thanks

Rube
04-26-2004, 08:42 AM
Hi Mark
Very NICE!!!
I don't know if to thank you for inspiring me to greater heights, or to hate you for dampening my spirits' cause I cant make one THAT NICE.

I just recently got interested in making a CNC, and was all over from retrofitting a purchased bench mill, to doing as you and making from scratch. I restore cars and build hotrods, so I need it to be able to whittle up aluminum and posibly even some steel brackets and such, so I think a wood or MDF frame is out of the question.

Why did you decide to go with steppers rather than servos for such a heavy unit? I thought servos were the way to go to maintain torque at speed (and you sure seem to have some speed, would be awsome to see that thing flying around!!).

Anyway, just HAD to chime in and say VERY NICE machine. And thanx for the inspiration, or damn you for crushing my enthusiasm...no really...THANK YOU for sharing!!!!!!!

Rube

rmtucker
05-07-2004, 03:52 PM
Well here is my next attempt,it's just an example from artcam with a few letters added but it gives the idea.

It's about 600mm high and took about 6hrs at 2000mm/min feed in 18mm thick mdf.

I have just darkened the high spots so the carving can be seen.

Mark

rmtucker
05-22-2004, 12:48 PM
Just call me Fred Flinstone.

I never in a million years thought my wood router would cut this with no problems.
This is really opening my options up.
The renishaw probe made this uneven rock a boon to draw and cut.

Mark
http://website.lineone.net/~rmtucker/

kong
05-22-2004, 01:42 PM
Wow Fred, that rocks:rainfro:
Sorry, couldn't resist, but seriously, that is some nice work. How hard was it on the router, and what kind of speeds can you carve stone at?

ullbergm
05-22-2004, 01:43 PM
Originally posted by rmtucker
Just call me Fred Flinstone.

I never in a million years thought my wood router would cut this with no problems.
This is really opening my options up.
The renishaw probe made this uneven rock a boon to draw and cut.

Mark
http://website.lineone.net/~rmtucker/

awesome

rmtucker
05-22-2004, 04:52 PM
Here is rock number 2

It's still wet so not too much contrast yet.
Kong this was done at a feedrate of 1000mm/min,it would probably do 4 times this but i can't nip my bum cheeks any tighter if you get my drift!!!!.

Mark

rmtucker
05-22-2004, 04:54 PM
Just another view to show the contour of this thing.

Mark

foamcutter
05-22-2004, 06:26 PM
Mark,
ok how are you getting the router to follow the contour of the stone? I am wanting to do something like that but am having trouble figuring out how to get the router to compensate for the varience in the surface. Thanks Ron

rmtucker
05-22-2004, 07:03 PM
Ron

I probe the surface of the rock first and read it into my cad cam system then project the toolpaths on to it.Then post back out to mach2 and machine.Mach2 makes a superb job of probing and machining,But i think it screwed my router bearings.
Maybe just Crap bearings.I will check tomorrow.

Mark

cbcnc
05-23-2004, 01:40 AM
Mark,

What are you milling the stone with? Wet?
I tried engraving a piece of granite tile. I put water on it and it still lit up my carbide cutter. It was just an experiment though. I guess diamond cutters are the only way.

Thanks,
Chris

rmtucker
05-23-2004, 05:04 AM
Chris

The stone was just wet off washing,It was cut dry with carbide with no problems.The cutter was just a 6mm shank with a 4 sided point ground on it (like a pyramid).

Mark
http://website.lineone.net/~rmtucker/

rmtucker
01-02-2005, 03:15 PM
Hi Fellas

Just getting back to my machine after months of other problems.I am going to build a congreve clock on the machine next See link for example.(http://www.williamcongreve.com/).
Thought i would maybe cut all the parts in one go ie,place sheets of brass on table 1/16" thick,3/32" thick etc.
Although the turned parts would have to be done on the planned cnc lathe.
Just tried a bit aluminium 1/16" thick and cut an example , it worked a treat.
I was thinking of maybe serializing my efforts on the zone if admin would maybe tell me where or which section/forum.
I need to get some serious cnc'ing done i think i got withdrawal symptoms.

Mark

kong
01-02-2005, 03:34 PM
Good to have you back Mark, I am sure the boss would love it if you would write it in the form of an article, which could then be posted in the articles section somehow! There was a post a little while ago asking for articles, but I lost track of where it is :(

ger21
01-02-2005, 07:32 PM
How'd you hold that thing down to cut it?

rmtucker
01-02-2005, 07:42 PM
Ger

I cut the inside first by clampng around outside then milled around the outside and left snap offs (Bridges) in 4 places about .004" thick so the job did not fall out.Then when complete you just press the job out of the plate.

Mark

cncadmin
01-04-2005, 09:48 PM
here you go

rmtucker
01-30-2005, 06:33 PM
Well i am taking the plunge and designing my own website around my homebuilt cnc router and my clockmaking projects.This is going to take up an awful lot of my time so i will be looking at the amount of visitors to my site and any feedback to see how far i should take this thing.

http://website.lineone.net/~rmtucker/

I am also hoping to update and give better descriptions of the building of the cnc to help some of the newbies out there.

Cnc Zone has been a source of invaluable help and encouragement to me and would like to thank all who answered and put up with my dumb questions.

I would say that i have finished the Cnc except for an operator panel and handwheel.

Please Remember that the website is under construction and will be changing on a daily basis so your patiance would be appreciated.

Once again thanks to all and i will still be lurking around the cnc zone every day.

Regards
Mark

chuckknigh
01-31-2005, 12:39 AM
Looks good, and I would like to see more about the Congreve clock you have shown. The history page just displays the word "History." :-) Of course, I'm a clock nut.

It looks like a very good beginning to a very good site.

Say, how did you engrave that rock? Did you design a toolpath to follow its contours? It looks like you followed the surface down the "step."

-- Chuck Knight

jeffs555
01-31-2005, 01:17 AM
Mark,
I am also quite interested in your clock. I knew about Congreve's rockets because you launched them against us nearly 200 years ago :-) but didn't know he invented a clock. I looked up his clock, and it is a most interesting design. I had never heard of a rolling ball clock before. It must be interesting to watch one in operation. I will eagerly watch your progress on your web site.

Jeff

rmtucker
02-25-2005, 02:59 PM
Hi Guys

Just follow the congreve project links on my website to see progress on the congreve clock.

http://website.lineone.net/~rmtucker/

Regards
Mark

rmtucker
04-05-2006, 02:55 PM
Hi guys

I have found a use for my cnc router at last,Go to my web page at:-
www.weardalecnccarving.co.uk
in the march and april sections of the vwtrike build.

It may not look much at the moment but when i start on the engraving,the yokes and anything else i can fit on the machine will be covered.
It May give someone some ideas.

Regards
Mark