G-code Workshop

CNC Laser Pro user guide

This is a phone and tablet app, not PC software, so it has limits: large files and images take longer to process, and detailed work is easier on a bigger screen.

If the laser doesn't fire, try M3 mode. If the power scale is wrong, set Max S to match your controller's $30 value (typically 1000 or 255).

Contents

How it works

Start by choosing what to engrave. A photo becomes a shaded or dotted engraving, a vector file (DXF or SVG) becomes a cut or outline, and text is turned into letters the machine draws. After you set the size and the parameters, the preview shows the result, and you can save the file or send it straight to the machine. You can pinch to zoom the preview.

Example workflows

Step by step examples from a loaded file to the finished program.

Laser engraving from a photo

1. Load the image. On the main screen tap Laser, then From Gallery or Take Photo, and choose the photo.

2. Edit. Crop away the extra parts, adjust brightness, contrast and gamma, and sharpen if needed. For dark material turn on invert.

3. Size. In the engraving parameters enter Width and Height in millimetres or inches (Laser size unit in the Menu). This is the real size of the image on the material.

4. Mode. Grayscale or Dithered work well for photos. Pixel size sets the detail, a smaller value is finer but slower.

5. Power and speed. Set the power and the speed. If you do not know the values, run a Material Test first and read them off it.

6. Origin. Choose Center to place the image in the middle. Position X and Position Y move the image from that zero point, in millimetres or inches.

7. Preview. Check the burn simulation.

8. Zero point and start. Set the work zero on the material, then Send or Save.

Vector cutting with the laser

1. Load the file. Import a DXF or SVG file in Laser Vector mode.

2. Power, speed, passes. Cutting needs high power and low speed. For thick material increase the number of passes.

3. Kerf. Enter the kerf value and direction so the finished part keeps its exact size.

4. Lead-in. Turn on lead-in so there is no burn mark at the start of the contour. On a closed contour it also needs a kerf direction.

5. Layers. If the file has layers, give each layer its own power and speed.

6. Origin and preview. Set the origin and check the contours.

7. Zero point and start. Set the machine zero, then Send or Save.

CNC milling

1. Load the file. Import a DXF or SVG file in CNC mode, or use text. Choose the unit (mm or inch).

2. Machining mode. There are three options. Engrave scores along the line without cutting through, for labels and patterns. Profile Outside runs outside the contour so the part keeps its size, for cutting a part out. Profile Inside runs inside the contour, for holes and inner openings.

3. Tool. Enter the tool diameter. For outside and inside profiles the cut is offset to the correct side of the line so the size stays accurate.

4. Depth. Enter the full depth and the depth per pass. The machine reaches the full depth in several passes so the tool is not overloaded.

5. Speeds and Z. Set the feed rate, the plunge rate and the safe Z height the tool lifts to when moving.

6. Profile settings. For outside and inside profiles choose climb or conventional milling, and add lead-in or a finishing pass for a cleaner edge.

7. Postprocessor. Choose your machine's controller.

8. Zero point and start. Set the zero in X, Y and Z, with Z on the material surface, then Send or Save.

Engraving a photo

Photos are engraved line by line. The mode decides how brightness becomes burn.

Modes

Dithered turns the photo into fine black dots. Grayscale changes the laser power so darker areas burn deeper. Halftone makes dots that grow larger in dark areas.

Main settings

Pixel size sets the detail and the engraving time. Power sets how strong the laser is, speed sets how fast the head moves. Smaller pixels and higher power give a darker, slower result.

Vectorize image (trace)

Turn a photo or logo (PNG/JPG) into vector lines so the laser can cut or outline-engrave it — not just raster-burn it.

Steps

1. Load a photo (from the gallery or by taking one). 2. Edit the image. 3. Tap Vectorize. 4. In the dialog, shape the outline with the sliders, then tap OK. 5. The image becomes a vector — set the cut settings, check the preview (pinch to zoom), and send it to the machine.

Where to set what

Size: on the engraving screen. Cut settings (power, speed, work area, origin, etc.): on the screen after vectorizing.

When it works well

High-contrast art, logos, line-art and silhouettes trace cleanly. Complex or photographic images will not trace well (true for every tracer) — use raster engraving for photos instead.

Levels (posterize)

Set Levels above 1 to split the brightness range into several nested layers — for example the whole silhouette on one layer and the dark detail on another. Each layer appears in the per-layer settings, so you can cut the outline and engrave the dark areas in a single job.

Outline vs Centerline

Outline draws closed contours around each shape (best for cutting or filled art). Centerline draws a single line down the middle of each stroke — ideal for thin line-art and fonts, so a stroke becomes one line instead of two parallel edges. Use Centerline for signatures, hand-drawn lines and single-stroke text; use Outline for solid shapes and cutting.

Tips

If the outline is messy, raise Despeckle or adjust Threshold. If it looks too blocky, lower Simplify. Use Invert for light art on a dark background.

Cutting with the laser

Import a DXF or SVG file. The app follows the outlines and cuts them with the laser. DXF files drawn in inches or centimetres and px SVG files come in at their real size.

Power, speed, passes

Set the power and speed for the material. Thicker material needs more passes, where the laser goes over the same line several times.

Kerf and lead-in

Kerf offset moves the cut by the value you enter: enter half the beam width so the finished part keeps its exact size. Lead-in starts the cut just outside the line, so there is no burn mark on the edge. On a closed shape (circle, rectangle…) the lead-in works only when a Kerf Direction is set, and it comes from that side: Outside from the outside, Inside from the inside. Holes inside a shape (e.g. the hole of a washer) automatically get the other side, so the whole part keeps its size. Whatever lies inside a closed shape (holes, engraving) is burned before that shape is cut out, so the part does not move first.

Layers

If the file has layers, each layer can have its own power, speed, and number of passes.

Laser text

Type any text, pick a font and size, and the laser engraves it. You can open it on the main screen from the Laser menu with the Laser Text button.

How it works

1. Type the text. Several lines are fine.

2. Choose a font, and bold or italic if you like.

3. Set the letter height in mm or inches. This is the height of a capital letter on the workpiece.

4. Choose the engraving mode, the power and the speed.

5. Tap Generate. The preview shows exactly what will be burned.

Which mode to choose

Fill burns solid letters. This is the usual choice for signs, gifts and labels.

Fill + outline does the same with extra sharp letter edges.

Outline burns only the edges of the letters. Use it for thin lettering or for cutting letters out.

Single line draws each line of a letter with one stroke. It is the fastest mode and the best one for very small text, below about 3 mm.

Fonts

You can choose from the phone's built-in fonts and the fonts that come with the app. The app fonts include script, serif, display, stencil and handwriting styles, and all of them contain every accented letter. With Import font you can add any TrueType or OpenType font from a ttf or otf file. Imported fonts stay available and can be deleted from the font list. Accents and other alphabets work when the font contains them. Fonts with very thin strokes need a larger letter height, and the app warns you about this.

Getting a clean fill

Line interval is the distance between the fill lines. Set it close to your laser spot size. A value between 0.08 and 0.15 mm suits most diode lasers. A smaller value gives a darker result but takes longer.

With overscan the head runs past the letters with the laser off, so the edges do not get darker than the middle. In M4 mode 0 is usually fine. In M3 mode use about 2 mm and leave that much free space next to the text.

Crosshatch adds a second fill at 90 degrees for an even darker and more uniform result.

Tips

Run a Material Test first to find the right power and speed for your material. Use Mirror when engraving the back of glass or making a stamp. The Size line under the preview shows the real engraved size in mm or inches. For text with several lines, use Alignment to place the lines on the left, in the center or on the right. Always check the result in the preview at the top.

Designer

Put text, SVG/DXF drawings and photos on one sheet and burn them together as one laser job. You can also draw shapes, repeat an item in a grid, and cut out text and shapes. Open the Designer on the main screen: Laser, then Designer. It works on a phone, but a tablet is more comfortable.

How it works

1. Tap Add and choose Text, SVG / DXF file, Shape or Image.

2. Drag the item to where it should be burned.

3. Select it and tap the three-slider icon below the sheet to set the font, size, power and speed.

The settings open in a panel that slides up from the bottom (phone only). When you are done, drag the panel down or tap the X at its top right to return to the sheet.

4. Add the other items the same way.

5. Tap Generate. The preview shows the whole job, and you can save it or send it to the machine from there.

Moving, resizing, rotating

Tap an item to select it, then drag it to move it. Drag the bottom-right corner handle to resize it, and the handle above the item (joined to it by a line) to rotate it.

Pinch with two fingers to zoom, and drag the empty area to move the view.

For exact values, type them in the item settings. Undo and Redo are at the top.

The sheet has rulers (mm or inches, set in the Menu) along the top and left edge; 0 is the sheet's bottom-left corner. They move with the zoom and mark where the selected item is. While you drag, the exact position, size or angle is shown at the top of the sheet.

Item settings

Tap an item: a bar with its name appears below the sheet. Its icons from left to right: circular arrow = turn an image by 90° (images only), three sliders = the item settings, two stacked pages = duplicate, grid array, combine (SVG / DXF and shapes) and photo in a shape, trash can = delete. On a tablet the settings are shown on the right.

Every item: position, size (letter height for text) and Mirror. Text, SVG / DXF and shapes also have rotation.

Above the X/Y fields you can choose Bottom left (the item's bottom-left corner) or Center (the item's center). The X/Y values and the readout while dragging refer to that point.

At the bottom of the settings: laser mode (M3/M4) and Max S, the same for the whole job.

Text settings

Text: the text, font, bold or italic, letter spacing, line spacing, alignment, engraving mode, line interval, power, speed and passes.

Cut (outline modes): the letters are cut out at the end of the job. Bridges leave 2 small uncut spots on the outer edge of every letter (letters that touch count as one; a very small letter is cut whole), so the letters stay in the sheet and do not fall or move; afterwards break them out. The insides of A, O, B… are waste and always fall out. For a stencil choose a stencil font. With Cut the passes are for the cut only; the fill burns once.

Arc radius bends the text around a circle (0 = straight): the circle goes through the middle of the capital letters of the first line; Arch puts the text on top of the circle, Smile under it. A top and a bottom text with the same radius and letter height share one ring. More lines bend around the same centre (outer lines get wider, inner ones narrower).

Resizing the text by dragging keeps its shape: the radius grows or shrinks with it. A letter height typed in the settings keeps the radius; if the text does not fit on that circle, the radius is raised to the smallest that fits.

SVG / DXF and image settings

SVG / DXF: engraving mode (Outline, Fill or Fill + outline), line interval, power, speed, passes, Cut, kerf compensation and lead-in.

On a closed shape the lead-in works only with the kerf direction Inside or Outside, and it comes from that side; holes inside a shape get the other side automatically. With Cut in Fill + outline mode the fill burns once; the passes are for the cut.

Image: image mode, line interval, brightness, contrast, gamma, black and white point, blur, sharpen, Invert, Reset All, material preset, power, speed, passes and overscan (for grayscale also bi-directional).

Shapes and grid array

Shape: tap Add, choose Shape, then the form: rectangle, circle / ellipse, polygon, star, heart or rhombus. It appears near the middle of the sheet.

In the settings you can set the width and the height separately, so a circle becomes an ellipse and a square a rectangle. A rectangle, a polygon and a rhombus can have rounded corners, for a polygon you set the number of sides, for a star the number of points. Inner size sets how deep the star's points are: a smaller number gives sharper points.

A shape burns like an SVG / DXF: outline, fill or cut, with its own power and speed. Cutting needs high power and low speed, thick material more passes; the right values for your material can be found with the Material Test.

Grid array: select an item, tap the two stacked pages icon and choose Grid array. Enter how many columns and rows you want and the gap between the pieces. The selected item stays at the top left, the copies go to the right and downwards. For example 4 columns and 3 rows = 12 identical pieces. One Undo removes them all.

Combine: select an SVG / DXF or shape, tap the two stacked pages icon and choose Combine…, then the other item and Union (merge into one), Subtract (cut the other one out of this one, e.g. a hole in a plate) or Intersect (only the common part). Only closed shapes count. The result is one new item with the settings of the selected one; you can undo it. Text can not be combined.

Photo in a shape (key ring, coaster)

Put a photo into a closed shape or a closed SVG / DXF: it burns only inside the shape, and the shape's line is cut out at the end.

Two ways: select a shape, tap the two stacked pages icon and choose Insert photo in its menu, then pick the photo; or select a photo and choose Put into shape… in the same menu, then pick the shape.

The shape and its photo are one item: moving, resizing, turning, mirroring, copying, a grid array and deleting the shape take the photo along. To move, resize or turn the photo inside the shape, choose Adjust photo, then Done. Take photo out makes it a plain image again.

In the shape's settings: Shape line (Cut, Engrave or None), Bleed (the photo runs this far past the cut line, so no white edge is left) and Leave out under filled items; turn on the Photo settings switch to set the photo's brightness, contrast and burning here too.

Key ring: draw an ellipse, put the photo into it, draw a small circle for the hole and switch on Cut for it, then put a filled name on top. The hole is cut before the outline, no photo burns inside it, and the name burns clean on the photo.

Position and burn order

The bottom-left corner of the sheet is the machine's 0,0 point, so everything burns where you see it.

The buttons at the top from left to right: page with a plus sign = New sheet, rectangle with corner marks = Workspace Size (the sheet size), arrow bending left = Undo, arrow bending right = Redo.

A red frame means an item is outside the workspace.

Images and fills burn first, then lines, and items marked Cut burn last. A cut lying inside another cut (e.g. a key ring's hole) is always cut first, so the piece does not move. Change the order with the arrows in the Items list.

New sheet, saving, reopening

The New sheet button at the top clears the sheet (you can undo it).

The sheet stays while the app is open. To keep it, tap Generate, then Save in the preview.

When you open it later from Laser saves on the main screen, the sheet also comes back into the Designer and replaces the one there; if the Designer already has a sheet, you are asked first.

Tips and limits

Each item has its own power and speed, and the power never goes above Max S.

For images a line interval of 0.1 mm suits most diode lasers. The line interval is also the image resolution: it replaces the Resolution and DPI settings of the single-image mode, and the DPI and pixel count are shown under it. A smaller value gives more detail but a slower job.

A sheet holds up to 50 items, at most 4 of them images. Undo steps are kept until you leave the Designer.

CNC milling (router)

For a milling machine the app uses a Z axis and a real tool. This mode is for routers and mills, not for lasers.

Engrave, outside, inside

Engrave follows the line. Profile Outside cuts around the part so you keep the shape. Profile Inside cuts a hole. Enter the tool diameter so the cut lands on the correct side of the line.

Depth

Depth is the full cut depth. Depth per pass splits it into several passes so the tool is not forced too hard.

Engraving text

Type your text, then choose a font and a size. The letters are turned into single lines that the laser or tool follows. Larger sizes come out clearer.

Laser settings

Material presets

Picking a material fills in the power and speed for you. These are generic starting points, not exact values — every laser is different (wattage varies), so fine-tune them for your own machine, or run a Material Test first. The fields stay fully editable.

M3 and M4

M4 changes the power with the speed and is the safest choice for engraving. M3 keeps a constant power. In both modes the laser is off during fast travel moves.

Max S (maximum power)

Set Max S to the same value as your controller's maximum power, which is the $30 setting on GRBL. The app never sends a higher number than this.

Inches or mm

In the Menu on the main screen, Laser size unit switches the sizes on the laser screens and in the Designer (width, height, position, letter height, workspace) between mm and inches. Fine settings such as kerf offset, lead-in, line interval and letter spacing stay in mm, and the speed stays in mm/min. The G-code is always in mm, so the burned size is the same either way. The CNC part has its own unit choice.

Halftone on GRBL

Halftone dots use a dwell time. On GRBL set $32=0 in the controller, otherwise the dots will not fire. With $32=0 the app turns the laser off while a job is paused (GRBL 1.1). If your controller still keeps it on while paused, use Abort instead of Pause.

Material test

This burns a grid of small squares, each with a different power and speed. Run it on your material, look at the squares, and use the settings of the one that looks best.

First connection: Setup wizard

The wizard creates a machine profile, so the app knows which machine to connect to and how. Open Menu → Setup wizard, pick your machine from the list (or “Custom / other”), choose the connection type (USB, Bluetooth or WiFi) and, if needed, the machine's address. The profile is saved, and you can use it right away on the Transfer screen.

Connecting by USB

Connect the machine with a USB data cable and an OTG adapter (on some phones OTG must be turned on in the settings and turns itself off after a few minutes), tap Connect, then allow USB access when the phone asks. The settings below must match your controller.

GRBL and similar

For GRBL, FluidNC, Smoothieware and Marlin use 115200 baud, 8 data bits, no parity, 1 stop bit, and no flow control. The app sends one line at a time and waits for the reply.

Older CNC controls

For Fanuc, Haas, Siemens and other older controls use the values from the machine manual. These are often 9600 baud, 7 data bits, even parity, and XON/XOFF or RTS/CTS flow control.

Connecting by Bluetooth

Pair first

Pair the machine in the phone's Bluetooth settings before you use it here, then choose it from the list.

If the search finds nothing

Turn on Location on the phone. Android needs it to scan for Bluetooth devices, even though the app does not use your position.

Connecting by WiFi

Network (TCP)

On the WiFi tab tap Add Profile, enter the machine's IP address (Host / IP) and port, save, then tap Connect.

• IP address: shown on the machine's display, on the controller's web page, or in your router's list of connected devices.

• Port: usually 23 for GRBL WiFi controllers (FluidNC, ESP32, ESP3D); some boards use another port (e.g. MKS DLC32: 8080).

• The phone and the machine must be on the same WiFi network. If the machine has its own WiFi hotspot, connect the phone to it.

• If the connection drops while mobile data is on, turn off mobile data.

• If it does not connect: guest networks often block devices from seeing each other, and the IP address can change after a restart (a fixed IP set in the router helps).

• Some laser brands' own WiFi works only with their own app. In that case use USB.

FTP upload

FTP sends the file to the machine. Enter the address, port, user name, password, and the folder where the file should be placed.

GRBL connection tips

Machine preset (quick setup)

When you tap Add Profile, the top dropdown lets you pick your machine (Raymoto, Vevor 3018, xTool, Atomstack, Sculpfun, NEJE, Ortur, AlgoLaser, Creality Falcon, Wainlux, Genmitsu). The name, manufacturer, model, connection type and baud rate fill in automatically — you only need to add the USB / Bluetooth / WiFi address. The preset loads the most common GRBL setup (USB, 115200 baud). If your machine won't connect or behaves oddly, check your machine's manual for the correct baud rate and connection type, then tap Edit to adjust — every field can be overridden.

"Machine in alarm state" window

After power-on, GRBL controllers usually start in alarm state for safety. If this window appears right after connecting, tap Unlock — the app sends $X and the machine becomes ready. This is normal, not a fault.

"Waiting for machine response…" message during send

While sending, the app waits for an "ok" reply after each line. If nothing arrives for 5 seconds, "Waiting for machine response…" appears; after 10 seconds it changes to a second message. On a long, slow move this is normal. If the machine is not moving, press Abort, then check the USB / Bluetooth cable, the baud rate, and that the machine is not in alarm or hold state.

Keep the app open while sending

Most laser controllers (GRBL) run the job while it is being sent, so sending takes as long as the engraving. The screen stays on until the job is done. Do not lock the phone or switch to another app while sending: that can stop the laser in the middle of the job. If the app is interrupted anyway (screen locked, a call, another app), it pauses the machine at once: come back and tap Resume. On WiFi, after a longer interruption the connection ends and the job cannot be continued. If you press Back while sending, the app asks before it stops the job.

Positioning (jog / zero / frame)

Position a job anywhere on the workpiece directly from the app — no camera needed. Works only with a GRBL machine that is connected and idle.

Jog the head

Use the step buttons (X/Y, plus Z for CNC) to move the head to the spot where the job should start. Pick the step size (0.1 / 1 / 10 mm) first.

Set zero here

When the head is over the start point, tap Set zero to make that the origin. The job then starts exactly there.

Frame the job

Tap Frame to trace the job outline — a low-power visible beam on lasers, or a safe-height move on CNC — so you see where it will land before running.

Laser dot (Fire)

Laser jobs only. Hold Fire: the laser lights at a very low power on the standing head, so you see where the dot falls on the material. Release it, jog, look again, then tap Set zero (X/\u2060Y).

For safety the laser is on only while you hold the button. It also goes off when you jog, set zero, frame, send, disconnect or leave the screen or the app, and by itself after 20 seconds. If the connection is lost while it is lit, switch the machine off. Wear laser safety glasses and never look into the beam.

When it works

Positioning is available only when connected to a GRBL machine and it reports Idle. The buttons are hidden otherwise.

Zero point

Corner or center

Corner puts the zero point at the bottom left of the design. Center puts it in the middle. Move the machine to the same point before you start.

Work offset

The work offset (G54 to G59) tells the machine which stored zero point to use. Leave it at G54 if you are not sure.

Saving and sending

Save the file

Under Export, Quick Save writes the G-code to the Downloads folder. Save As… lets you choose any location or a USB stick. QR Code works only for very small jobs.

Send to the machine

Send transfers the program straight to the machine over the USB, Bluetooth, or WiFi connection you set up.

Saving and reopening a program

In the preview, tap Save to store the finished program in the app under a name of your choice. Saved programs appear on the main screen under two cards, Laser saves and CNC saves: tap a card to open its list. Tap one and choose Load to open it again in the preview, where you can export it or send it to the machine. Delete removes it from the list.

Related: FAQ, supported machines.

By Miguman, CNC machine operator, programmer and toolmaker with more than 25 years of experience. Updated .