HERCUS Mill Retrofit

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Commotion
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HERCUS Mill Retrofit

Post by Commotion » Wed Jan 03, 2018 6:01 am

Hi Gents,
I thought i would start a thread to show my side project. I picked up an old HERCUS DTM320 from a mate who is a high school tech teacher and has accumulated a bunch of old desktop mills and lathes from his school over the years.
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The servo drivers were missing from the cabinet as apparently the machine has done very little work and kept blowing something. It had a breakout board with a serial plug and a bunch of IO and rectified and what not. It may have had the motor control imbedded in the board or the rectifiers may have just been to generate DC power for the DC motors. either way the tracks are fried.

It appears as though a manual mill/drill has been used as the basis for the milling machine as it a bunch of holes and unused cavities in the head which im assuming were for different gear ratios and quill feed.
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I stripped it down to figure out how best to go about retrofitting new control gear. I have removed the old DC servo motors and have 2 leadshine AC servo motors and 3 servo drives spare from when we bought our plasma cutter for work. I will need to source a third servo motor but am surprised at how much they cost on ebay. I ordered my acorn board and it arrived just in time for Christmas. I have an old Z400 workstation which i have setup as my CNC PC and will eventually get a touchscreen monitor for it. I bought an omron 2000ppr encoder for the spindle and have wired it up and tested it to be functioning correctly. The shafts on the servos are 14mm and too big to fit the original pulleys so i orders larger ones and machined them to suit the servos. I have ordered longer belts which should arrive in the next day or two.

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I have had some trouble getting the NC control to move the servos properly but after much searching online and on here i think my problem has been me trying to shortcut. It would only rotate one direction and very slowly, as soon as i bumped up the speed it would lock up. i thought it might have been set to double pulse but i eventually got a comm cable to work so i could access the drive with protuner and it seemed to be set right. i was too impatient to order the leadshine tuning cable so i used a db9 plug and cut up a rj11 phone plug to make a cable. it took a bit of experimenting but finally got it to work. I can share the wiring arrangement if anybody is interested. Weirdly the RX and TX in the leadshine manual for the drives means RX and TX on the db9 plug not inverse like most are.

Instead of using a separate power supply for the step and direction commands i used pin 19 on the drives which is a 5v output but after going back and reading the specs on the drives this output is only 10mA. I have ordered a dual voltage power supply and am waiting for that to arrive to see if it fixes it.

This is what my cabinet looks like so far.
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Luckily as it was already a cnc machine it has the limit switches already in place so next job is to wire them up while i wait for my power supply and timing belts to arrive.

My main unknown has been the spindle motor. It has a 230VDC 600W motor which is what my post was about. Dickybird posted some interesting info and although i had come across a couple KB motor controller and got some pricing from some local suppliers none had suggested the KBCC. I have however already ordered a cheap 1.1kW VFD off eBay and will see how fast i can spin up some old 3ph motors i have laying around.

The other thing which is a bit strange is the Z axis arrangement. It has a ACME thread looking screw with what i would imagine is a rotating nut and worm drive arrangement. I guess this is so the head doesnt sag without power to the drives. At first look there is a tonne of backlash in this arrangement but a lot of that is axial play in the worm shaft and bearings and housing. It also looks like the ratio of rotations to travel is much greater than the ball screws so i would probably change the gear ratio to get a similar rotations to travel ratio as the ball screws so i have similar travel speeds. I would be thinking the servos are plenty big enough.
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pulsenpal
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Re: HERCUS Mill Retrofit

Post by pulsenpal » Wed Jan 03, 2018 11:48 am

I was given a Hercus cnc lathe 25 yrs ago--educational bench model--OZ built
and unrivaled with regard to heavy castings, working 6 tool turret, headstock

but---entire control system /power components were mounted on single massive circuit board in base of machine--and these boards
all failed

worthwhile iron for control update

pic is not my machine but similar
Attachments
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DICKEYBIRD
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Re: HERCUS Mill Retrofit

Post by DICKEYBIRD » Wed Jan 03, 2018 12:12 pm

Commotion wrote:
Wed Jan 03, 2018 6:01 am
My main unknown has been the spindle motor. It has a 230VDC 600W motor which is what my post was about. Dickybird posted some interesting info and although i had come across a couple KB motor controller and got some pricing from some local suppliers none had suggested the KBCC.
Sorry, my bad. As usual I spouted off at the keyboard before totally understanding the situation. :oops: I must've subconsciously ignored your clearly stating it had a 230VDC motor. Marty, as usual, clarified that in your other thread. I'll crawl back under my rock now. ;)

ps: Very nice machines, can't wait to see 'em running!
Milton in Collierville, TN

"Accuracy is the sum total of your compensating mistakes."

ScotY
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Re: HERCUS Mill Retrofit

Post by ScotY » Wed Jan 03, 2018 12:37 pm

Looking at the pic of the truck, he must be from Aus or NZ. They’ve got the coolest trucks down there, many of which have flat beds and racks, all made from aluminium. :lol:

Commotion
Posts: 42
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Re: HERCUS Mill Retrofit

Post by Commotion » Wed Jan 03, 2018 5:19 pm

pulsenpal wrote:
Wed Jan 03, 2018 11:48 am
I was given a Hercus cnc lathe 25 yrs ago--educational bench model--OZ built
and unrivaled with regard to heavy castings, working 6 tool turret, headstock

but---entire control system /power components were mounted on single massive circuit board in base of machine--and these boards
all failed

worthwhile iron for control update

pic is not my machine but similar
The guy i got the mill off also has two hercus lathes of different sizes. I dont remember the model numbers. he messaged me saying he was going to dig out the control computer and see if it still worked. I advised him to jump on the acorn bandwagon before prices go up.

He also has an emco lathe with rotary tool changer and an emco with dead servos. He also has an Adept mill/lathe thing which i am storing for him while he does some renos (why he was happy to give away the hercus to make more room)
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Last edited by Commotion on Wed Jan 03, 2018 5:34 pm, edited 1 time in total.

Commotion
Posts: 42
Joined: Mon Jan 01, 2018 6:47 am
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Location: Bisbane Australia

Re: HERCUS Mill Retrofit

Post by Commotion » Wed Jan 03, 2018 5:30 pm

ScotY wrote:
Wed Jan 03, 2018 12:37 pm
Looking at the pic of the truck, he must be from Aus or NZ. They’ve got the coolest trucks down there, many of which have flat beds and racks, all made from aluminium. :lol:
A keen eye you have, yes Australia. We get screwed over for prices on a lot of things but i my opinion one thing was have always had over the US is nice looking vehicles. All local car manufacturing has now closed down so lets see how long it stays like that.

I went to CA for a holiday a year or two ago with the wife and absolutely loved it. Drove up to san fran and then back down doing all the scenic places. Friendly people and i love that the authorities have a sensible view on road policing. Only thing that i would find difficult to deal with is the imperial units and no tax displayed in advertised prices. If i ever moved to the states i would have to find a way to get our Ford Falcon over there. I love this thing nice and comfortable with bulk power (450rwhp).
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ScotY
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Re: HERCUS Mill Retrofit

Post by ScotY » Wed Jan 03, 2018 9:58 pm

That’s a sweet car but the steering wheel is on the wrong side. :lol: I can say the same about Australia...awesome country with great people!

martyscncgarage
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Re: HERCUS Mill Retrofit

Post by martyscncgarage » Thu Jan 04, 2018 8:38 am

Very neat machines and good examples of dedicated CNC machines that can be found for retrofit.
I'll be following your builds.
Marty
"Jack of all trades, master of none!"
Mesa, AZ

Commotion
Posts: 42
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Re: HERCUS Mill Retrofit

Post by Commotion » Thu Jan 04, 2018 8:59 am

I have gotten the guy i got the Hercus off all inspired and he has ordered an acorn board now. Lets hope he follows through and gets one of the hercus lathes up and running.

To give you some background on myself im a Mech Eng by profession and am managing the family manufacturing business at the moment. We build earthmoving equipment, mainly laser buckets or scrapers or drag buckets as they are called in different parts of the world. I taught myself how to program our CNC equipment after our operator left probably 12 months ago or so. Our mill is big and old which is the main reason i started looking at retrofitting an old desktop mill so i can machine up some small aluminium components as its super slow with the big old mill and 3150rpm max spindle speed. We have however purchased another newer and smaller Mazak VTC mill which should be arriving within a week so i'm super excited about that.

the old mill and our lathe
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And this is some photos of the machines we build:
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pulsenpal
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Re: HERCUS Mill Retrofit

Post by pulsenpal » Thu Jan 04, 2018 10:20 am

pics of your graders trigger recall of RG LeTourneau and his chronicleer ---australian Philip Gowenlock
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