Start point impression

[tnsreenivasan]

Start point line impression.
MITSUBISHI MV1200S.

Dia 7mm Hole in 10mm Thickness
Material : Steel
Wire used Dia 0.20
No of Cut : 4
Start Point mark visible in 40x Zoom as marked/shown in the picture

Finish and start point mark was good, if we observe normally.

But, Customer inspected the profile with microscope with 40x zoom. And found start point impression as shown in the pic.

Pl share any experiences in this.
Thanks
Sreenivasan

 

[implmex]

Hi Sreenivasan:
There are a couple of ways I know of to reduce or eliminate the marking of the part that occurs where the wire starts and stops on the profile.
The first is to ease into the part contour with an arc move.
The second is to turn off corner control
The third is to alternate the direction of each skim pass.
The fourth is to change the start point of each skim pass.

I have found the first option to be pretty good.
The second option is also very effective.
The third has not worked all that well for me
The fourth has been best if combined with the first and second.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

 

[tvalen1432]

I have found that rotating each pass 90 deg. from the prior pass with a fairly good size arc lead in and out works great. Make every other pass a reverse pass as well and you should be good. When that line matters I use more passes to get to size. If they are that picky of the line, make the last 3 passes barely taking off material. For example passes look something like this:
#1-E1341 F.04 H1=.0081
(FW pass)
#2-E1342 F.12 H2=.0061
(Rev with a K90.)
#3-E1342 F.12 H3=.0058
(Fw pass with K180.)
#4-E1343 F.18 H4=.0056
(Rev pass with K-90.)
#5-E1344 F.22 H5=.0056
(FW pass)

If not quite to fit I add additional pass E1344 F.22 H6=.0055.
feeds may vary but don't be shy to run more passes using E---4 repeating same offset distance.
Some may say that's over kill or electro polishing but to get rid of the line for a picky customer you do what it takes.
Also on my machine settings it has a setting called EM where you can have the machine offset to eliminate it as well. I have a MV2400S Mitsubishi.

Good luck
Tvalen1432

 

[tnsreenivasan]

Hi Sreenivasan:
There are a couple of ways I know of to reduce or eliminate the marking of the part that occurs where the wire starts and stops on the profile.
The first is to ease into the part contour with an arc move.
The second is to turn off corner control
The third is to alternate the direction of each skim pass.
The fourth is to change the start point of each skim pass.

I have found the first option to be pretty good.
The second option is also very effective.
The third has not worked all that well for me
The fourth has been best if combined with the first and second.

Cheers

Marcus
www.implant-mechanix.com
www.vancouverwireedm.com

Hi Marcus,
Thanks for your suggestion. I tried all above except the first one.
Will try and check.

Thanks once again.
Sreenivasan

 

[tnsreenivasan]

I have found that rotating each pass 90 deg. from the prior pass with a fairly good size arc lead in and out works great. Make every other pass a reverse pass as well and you should be good. When that line matters I use more passes to get to size. If they are that picky of the line, make the last 3 passes barely taking off material. For example passes look something like this:
#1-E1341 F.04 H1=.0081
(FW pass)
#2-E1342 F.12 H2=.0061
(Rev with a K90.)
#3-E1342 F.12 H3=.0058
(Fw pass with K180.)
#4-E1343 F.18 H4=.0056
(Rev pass with K-90.)
#5-E1344 F.22 H5=.0056
(FW pass)

If not quite to fit I add additional pass E1344 F.22 H6=.0055.
feeds may vary but don't be shy to run more passes using E---4 repeating same offset distance.
Some may say that's over kill or electro polishing but to get rid of the line for a picky customer you do what it takes.
Also on my machine settings it has a setting called EM where you can have the machine offset to eliminate it as well. I have a MV2400S Mitsubishi.

Good luck
Tvalen1432

Hi Tvalen1432,

As you suggest, will try and check.

Thanks once again.
Sreenivasan