Z offset when cutting

Discussion on what materials you laser cut or engrave
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Bob Marino
Posts: 16
Joined: Mon Mar 08, 2021 7:41 am
Location: Boston, MA
Country: United States
Nickname: byteman59
Laser Machine Make or Type: DIY RDC6445G
Laser Power: 50
Laser Bed Size: 800mmx600mm
Home Position: BR
Control Software: LIGHTBURN
RDWorks Version: 8.01.18
Ruida Controller: RDC6445
Windows Version: Windows 10

Is it best to use Z offset when cutting material?

For example,
Focus is 5mm from Tip of laser
Wood Material is 3mm thick

Should i use an offset of 1.5mm?
What about for 6mm material? 3mm Offset?

What is best practice?

Thanks
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Gene Uselman
Posts: 2161
Joined: Thu Jul 07, 2016 3:18 pm
Location: Suburban Minneapolis, Minnesota, US
Country: USA
Nickname: Gene
Laser Machine Make or Type: QC
Laser Power: 130W
Laser Bed Size: 900x1300
Home Position: TR
Control Software: LIGHTBURN
RDWorks Version: RDw .19 & Lightburn
LightBurn Version: Latest
Ruida Controller: RDC6442
Windows Version: Win 10 Pro
Accessories: I have a combining lenses, pin tables [homebuilt], honeycomb tables , wireless remote, Modifed Ultimate Air Assist, home built non-powered rotary device, PrusaMK4 and Mini Prusa printers.

I don't really take that into consideration unless the material is approaching the limit of my laser- then sometimes it is helpful. I have a lot of power- your results may vary.
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BT48 Alpha Shopbot and 1300x1800 130W Laser

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Ray Wylie Hubbard
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sebastien laforet
Posts: 143
Joined: Wed Sep 07, 2016 3:23 am
Location: Lyon
Country: France
Laser Machine Make or Type: bodor BCL0605MU
Laser Power: 100W
Laser Bed Size: 60*50cm
Home Position: TR
RDWorks Version: 8.01.19
Windows Version: 7

for 3mm material, the difference will be barely visible, unless you use a very short focal length.

with a 1.5" focal, and 6mm material, it begins to be useful to lower the head by 2mm. in my experience, it is not the best to target the exact middle of the material.

with a 2,5" focal, this makes no difference offsetting the head for such a small distance.
Sébastien Laforet
machine : Bodor BCL-0605 (60x50) with 100W laser with TR origin.
Live in France
Primarily works laser for my wife (school teacher, so lots of boxes, letters, puzzles, ...) and miniature scenery (32mm scale : warmachine, infinity)
User avatar
Gene Uselman
Posts: 2161
Joined: Thu Jul 07, 2016 3:18 pm
Location: Suburban Minneapolis, Minnesota, US
Country: USA
Nickname: Gene
Laser Machine Make or Type: QC
Laser Power: 130W
Laser Bed Size: 900x1300
Home Position: TR
Control Software: LIGHTBURN
RDWorks Version: RDw .19 & Lightburn
LightBurn Version: Latest
Ruida Controller: RDC6442
Windows Version: Win 10 Pro
Accessories: I have a combining lenses, pin tables [homebuilt], honeycomb tables , wireless remote, Modifed Ultimate Air Assist, home built non-powered rotary device, PrusaMK4 and Mini Prusa printers.

Russ has been exploring this lens focus question in a lot [a lot] of detail... I am not sure he has any conclusions yet
If the Help and advice you received here was of VALUE...
Please consider making a donation to maintain the RDWORKSLAB Forum.

BT48 Alpha Shopbot and 1300x1800 130W Laser

The days that I keep my gratitude higher than
my expectations, Well, I have really good days.

Ray Wylie Hubbard
Bob Marino
Posts: 16
Joined: Mon Mar 08, 2021 7:41 am
Location: Boston, MA
Country: United States
Nickname: byteman59
Laser Machine Make or Type: DIY RDC6445G
Laser Power: 50
Laser Bed Size: 800mmx600mm
Home Position: BR
Control Software: LIGHTBURN
RDWorks Version: 8.01.18
Ruida Controller: RDC6445
Windows Version: Windows 10

Thank you both for your comments. I will use your opnions to guide me.
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