Functional operation

Q: How to fix Homing Fail/Alarm 8/Alarm 9?

A: Click here to see the steps


Q: How to flash firmware-LE400PRO?

A: Click here to see the steps


Q: How to flash firmware-LE400PLUS?

A: Click here to see the steps


Q: Troubleshooting Lightburn

A: When you have problems with Lightburn. Please follow the steps below to slove it.  

Troubleshooting Lightburn
Fehlerbehebung Lightburn

Note: Please remove all the device you have created before.
In order to differentiate the device, you can give a name for the new device.


Q: How to deal with the reverse direction movement or mirror image of the carving?

A: Change the settings as shown in the link.

EN-The engraving is in reverse or mirror image

DE-Die Gravur erfolgt seitenverkehrt oder spiegelverkehrt


Q: The laser size does not match the original size. Such as Original size 39x39mm, laser size 62x62mm 

A: Solution: Click here


Q: What is the laser precision and engraving area?

A: The laser precision of our engraving machine is 0.08mm, using point compression technology, square ultra-fine focused laser, which can achieve more precise engraving and cutting. The engraving area of the machine is 400*400mm, meet your engraving need for most items.


Q: How long is the working life of the laser?

A: After accumulating about 15000-20000H, the laser power will be reduced by 15%, but it can still be used for simple engraving.


Q: Is it necessary to have an exhaust system for it?

A: You need it if the object you engraved emits an unpleasant smell.


Q: There is no laser beam appears.

A: Please check that your cables are properly connected and secure and check each component. The 3 rows of cables on the main chassis confirm that the laser module is connected correctly.


Program Parameter

Q: What are the applicable engraving software and systems?

A: Operating software: LaserGRBL, LightBurn, Benbox, GrblController, LiteFire. Support system: Win XP / Win 7 / Win 8 / XP / Win 10/Win 11.


Q: What is the Laser output optical power of KENTOKTOOL LE400 Pro laser?

A:  The output power of the laser is 5.5W, the maximum power of the total machine is 50W( including the main board and the motor).


Q: Are there default settings of various materials for engraving or cutting?

A: There are no default preset parameters in the software. We have introduced the engraving and cutting recommended parameters in our user manual, you can adjust them according to your material and thickness.


Q: Page EN-11 that Flash Grbl Firmware settings of the old instruction manual cannot be operated

A: You can engrave directly after installing the driver without others operation.


Q: What laser settings must be set in the software for the laser to be used? There are many lasers to choose from in LaserGRBL software.

A: If you want to engrave, in the conversion tool, select line to line tracking or 1bit bw unrest (tremor). 1bit bw unrest (tremor) is more layered.
Then enter the speed value in speed and choose M3 for laser mode to keep the laser power constant.
If you want to engrave a layered pattern, you can choose the M4 dynamic laser, then input the value of S-MIN and S-MAX to adjust the laser power according to the characteristics of the engraving object.
If you want to cut, select Center line, enter the limit speed, and select M4 for laser mode to keep the cutting surface smooth. Finally, enter the values of S-max and S-min.



Q: LaserGRBL parameters can not be adjusted back after the adjustment?

A: Import the following parameters.



Q: LaserGRBL can not directly engrave after zeroing?

A: Pay attention to the setting offset, as shown in the figure.


Q: How do I need to adjust the laser module loosening?

A: Follow this video step.

Q: About the lightburn engraving size discrepancy, how do I need to solve it?

A: Click link and follow the step.


Engraving Material

Q: What materials can be engraved?

A: Wood, bamboo, cardboard, leather, plastic, acrylic, non-woven fabric, metal plate and other paper, PCB board, alumina, non-reflective electroplating surface paint.


Q: What materials can be cut?

A: Cutting material: thin wood board, cardboard, non-woven fabric, thin acrylic and thin plastic board.


Q: What is the maximum thickness of wood that can be cut by this machine?

A: Plywood from 1mm to 12mm and solid wood from 1mm to 10mm can be cut by this machine. Its high performance determines its working intensity.


Q: What is the maximum thickness of wood that can be cut by this machine?

A: Plywood from 1mm to 12mm and solid wood from 1mm to 10mm can be cut by this machine. Its high performance determines its working intensity.


Q: What values can it use to cut 10mm solid wood panels or solid wood?

A: Cut 10mm solid wood panels or solid wood, select the center line of forming tool, speed 200mm/min, laser mode M4 dynamic power, S-min select 100, S-max select 1000, recommended 50 times. The distance between the protective cover and the board is 3mm.During the cutting process, set the knob according to the cutting depth to move the laser focus downward. As the engraving gets deeper, it is recommended to adjust the laser down knob so that the distance between the laser and the board is below 1mm to achieve the highest laser cutting efficiency.


Q: What settings are used to cut 3mm thick poplar wood lumber?

A: Performance: 100%,Speed (mm/min): 110,Number of passes: 1,Laser option: M3.


Q: How to cutting values for 4mm thick plywood?

A: For 4mm boards, the following parameters are recommended.
Performance: 100%
Speed (mm/min): 80 (if the machine default setting is mm/s, change the value to 3)
Number of passes: 1
Laser option: M3

If you are using Lightburn software, you need to switch to "Edit" under "Convert to Cut" when cutting
Then change the "Mode" to "Line"
When cutting 4 mm wood, the following parameters are recommended.
Maximum performance: 100%
Minimum performance: 100%
Speed (mm/min): 110
Number of passes: 1


Q: Does it engrave metal?

A: The product can engrave metal. First, you need to blacken the metal surface (using the blackening pen included in our package), adjust the LaserGBRL speed to less than 200, and adjust the laser power to 100%, and choose to run it multiple times according to the effect you want to achieve.


Q: Does it also cut thin metal with the LE400PRO?

A: It depends on the thickness of your thin metal. If it is like paper then you can try it. It is recommended to reduce the speed to below 200 and set the laser power to maximum. Please take precautions during the cutting process and place steel or honeycomb plates on the tabletop.


Q: How to use it to engrave a 42.4 diameter stainless steel tube, polished with 240 grit, or the surface must be mirror-smooth?

A: This is no problem. The surface of the stainless steel tube must be blackened. Blackening can better absorb the laser energy and prevent laser loss due to the reflection of the laser by the smooth lens. It is recommended that you have a swivel axis for better engraving work. The swivel axis can keep the focal point and the object to be engraved at the same height during the engraving process.


Q: Can LE400PRO cut 3mm aluminum? The surface is matte and non-reflective?

A: Sorry, it cannot cut aluminum. We consider your expectation and implement this feature in the next-generation machine. Thank you for your interest and support.


Q: Can it engrave polished stainless steel? Does the material have to be flat?

A: LE400PRO can engrave polished and brushed stainless steel. If it is polished stainless steel, it is recommended to blacken it before engraving for better results. It is possible to engrave curved material using the shaft attachment of the engraver, but this must ensure that there are no uneven marks.


Q: How can laser work on the part? For example, for knife carving

A: Use the supplied 2mm plastic plate to adjust and keep 2mm distance.


Q: Does it engrave or cut acrylic?

A: It can cut black acrylic within 5mm or engrave white transparent acrylic.


Q: How to engrave acrylic sheet? Engrave clear acrylic so that the image or text becomes white.

A: 1. Before engraving, blacken the acrylic board with a black pen or black powder. Draw only the area you want to engrave. (Blackening is to better absorb the laser energy and avoid laser reflection caused by smooth acrylic surface. If there is no blackening, the acrylic melts or engraving will not successful.)
2. Place our black steel plate on the bottom. Use an object to support the acrylic plate and keep a hollow space between the acrylic plate and the steel plate.
3. After opening the file on your computer, please select the center line of the engraving parameters. The recommended speed is 3500 mm/min. In M3 mode, input 100 for S-min and 500 for S-max.
4、When scanning, it is recommended to elevate the laser and keep a large distance from the acrylic plate. When you are ready to engrave, turn the laser down to start engraving. This way the scanned laser line will not be engraved on the acrylic board. We recommend setting the distance between the laser and the acrylic board to 3 mm.
5. After engraving, wipe off the black paint with a paper towel.
This is how you get a successful acrylic engraving pattern.


Q: Can it cut black acrylic? (about 1.5mm)

A: LE400PRO can cut acrylic, all acrylic sheets up to 7mm. If your material is black, there is no need to blacken it and then cut it.


Q: Does it engrave paper?

A: Yes, but need to adjust the speed up and reduce the light power.


Q: Can it engrave round objects like pen holders and bottles?

A: Yes, our laser engraving machines can engrave round objects, but need requires an additional roller. Just connect the machine with it, you can engrave and cut them easily.


Q: Steel surface engraving parameters.