Daewoo Ace V400

[rags]

we are looking to buya used daewoo ace v400 vmc- Fanuc 18m-Twin Pallet, yom 2000, any opinoins on this machine and most common problems related to this machine.

thanks
rags

[ragman]

There was one of these where I once worked a few years ago. It was apretty good machine. No major problems and was reliable. The biggest issue which comes to mind was the lube oil feed lines - on this mill, they must have used the wrong tubing because it reacted with the slideway oil and fell apart literally. Was a time consuming job to re-route all the lines, but it had to be done. Other than that, the hydraulic unit would trip out sometimes - Power off then on to clear it. They never got to the bottom of that one. Sometimes the pallet would stay up after indexing as well.
It took some mighty hits in the time I was there but seemed to maintain it's accuracy.
Overall an ok machine.

[Retrolaw]

Hello there, Rags.

I know that it's a bit late, but I've just joined and seen your post now.

As Ragman mentioned, the machines are good and solid. We have four of the V430 machines at our factory. They are machining brass and aluminium products, which are held in position by hydraulic "Schunk" chucks. Our oldest machine was bought in 2004. The problems that we've had over the years are minimal, but I will list them so that you can look out for them and fix them if/when they crop up.

Spindle/Axis Communication error:
Problem: The cards it the spindle amplifier and axis controllers used to occasionally lose contact, from the plugs that the boards were mounted in. This was due to the the sometimes violent shakes, when the machine would rapid from point to point.
Solution: We asked the technician to change the "ramping speed" from the standard 64 milliseconds, to 128 milliseconds. This made the machines acceleration into, and deceleration out of rapid mode slightly slower. The machines don't shake now, and our problem is gone.

Table not dropping into clamped position:
Problem: The machine would chew up our jigs and tools, when it started to machine, while the table was still raised. The first cause was the hydraulic oil getting too cold in winter, relative to the summer temps. Our winters aren't cold (min -1ºC) but our summers are quite hot (max 48ºC) So now the damper on the table-swing mechanism would make the swing, a lot slower in winter (thicker oil) The table clamp sequence would land up pulling the table down before it was lined up with the locating pins underneath. So the would land up sitting on top of these pins instead of pulling down in line with their mating bushes. The second cause was that the two limit switches at the base of the swinging column, were sticky. So the one that registered that the table was down (clamped) would register that the table was clamped, even when it wasn't. So the machine got the "go-ahead" and milled right into our jigs. No harm done to the machine, by the way.
Solution: Ceramic elements can be fitted to keep the oil warm (above 20ºC). This keeps you from having to adjust the dampers every winter. Then more importantly, we now swing the tables manually 5 times before the start of a shift. We also spray the two switches with Q20 when the machines are cleaned on a Monday morning (running 24/7)

Low through spindle coolant pressure:
Problem: The newest machine that was only 14 months old, had a sudden drop in through spindle coolant pressure. The pump was running and the coolant filter bag was clean.
Solution: The technician found that a tiny piece of brass swarf had gotten stuck in the seat of the pressure relief valve of the pump. The pump was a lobe/gear pump, and isn't recommended for our use. Quick-fix was to clean the valve out and everything was fine after that. Long term solution was to buy a multi-stage impeller pump. It could easily handle the odd bit of swarf, but we needed to modify the coolant tank, to fit the pump as the pump is much longer and not as compact.
Problem: The oldest machine which is now just over 4½ years, also had a sudden drop in pressure. The problem turned out to be that the steel ball in the pressure relief valve had worn badly. It had a groove around it which only matched the seat, if it sat in a very specific position. Once it moved from that position, it wouldn't seal and all the pressure was lost. Unfortunately the agents wanted to sell us a complete pump and motor, instead of just the relief valve.
Solution: Modified the tank to take the same multi-stage pump as the other machine. These pumps are easier to get individual parts for and they are also serviceable.

Hydraulic pump damaged due to low oil level:
Problem: The hydraulic tank is tucked away behind the machine and nobody would check the oil level, until the error came up that the pressure was low. By this time the pump had been starving for a bit, especially during a table swing (uses a lot of oil to lift and clamp the table). After this happening quite a few times, the pump started to sustain damage and eventually packed up altogether.
Solution: We got the technician to fit a float switch to the tank. He wired it in with the hydraulic pressure switch, which is right there on the output of the pump. Now when the oil level drops, you get a message on the screen saying "Oil Pressure Low" and the machine shuts the pump down. Then you just top the tank up and your back in business and the pump hasn't been harmed at all. Just remember to make the "low level" quite safely above the intake of the pump and you'll be fine.

Other than that, these machines have really served us well. They've taken a few knocks, when we were still learning how to program them (we don't have any simulation software). But they are still running very well. The biggest help is that they are cleaned really properly and this makes much easier to spot the occasional oil leak, from a chafed hose or a damaged central lube pipe. I would recommend putting a split piece of pipe around the hoses that lift and lower the table, just on the corners where the pipes rub against the cast sub-frame of the machine. The pipes are 4meters long and cost a reasonable amount. Plus the are a bit of a mission to fit as they do an "S" bend just before they pop out at the back of the machine. If you do pull the old ones out, tie a piece of wire around the end of the pipe, so that you can pull the new pipe through with the wire. We used some rubber, mining hose to put over the hoses, on the corners were the old ones chafed through.

One last, last thing. If ever the machine drops a tool out of the spindle when it is executing a tool change, check if the yellow push-button light on the side of the spindle stays on. If it is on, this means that the machine didn't pick up that the tool was in the spindle and ready to be clamped. More importantly, it hasn't updated the tool list, so it still thinks the old tool is in the spindle. If you put the tool back in the spindle, by hand. The machine will crash it. The thing to fix, is the proximity switch on the cam behind the tool magazine. If you slide the large side door open and look across the table, past the spindle, you will see a cover that gives you access to the back of the magazine. Remove the cover and look towards the left back, and you will see 3 proxy switches. They only have a 2mm sensing range and one may be just too far to pick up the cam every time, reliably. Switch the machine to jog mode. Put the tool changer remote control onto manual. Orientate the spindle. Drop the tool pot to spindle side. Step the tool changer forwards until it is putting the tool right up into the spindle. Stop, just before the arm starts to swing back towards home position. Then push Emergency stop and open the little inspection door above the chip conveyor (left of the magazine). This will stop the machine from executing a tool change while your hands are inside adjusting the proximity switches. Then hop around the other side and into the machining cabinet. You will see that one of the proximity switches is really close to the rotated cam. The thing is that it probably isn't close enough. Use a feeler gauge and adjust the proximity switch/sensor so that it has a 0.5mm gap to the cam. After that you can reset the emergency stop and complete the tool change (you may have to step it backwards). Then your machine shouldn't drop tools out of the spindle when it does a tool change. PS: Dropping tools out of the magazine side, when doing a tool change requires re-alignment of the tool changing arm.

Anyway, that it for now. I hope that you've already had a good few months of reliable service from your machine, so far.

Cheers for now.
Retrolaw.

[rags]

Thanks Retrolaw,
The v 400 is doing great and we are indeed happy with it.I will make note of the issues in your post which is most usefull.

Thanks again \

Rags

[rags]

Thanks again Retrolaw,

I forgot to add , the v400 is a vert turning centre- your v430 must be a VMC... any way cheers

rags