Free tool · STEP · No registration
Can your part be machined? Check it for free before requesting a quote.
Upload the STEP and we check it the way the person programming the mill would: internal radii, walls, holes, slots and areas with no access. In red, what can't be made as drawn. In orange, what can, but makes the part more expensive or puts it at risk.
Drop your part here
With the STEP we see every face exactly as you drew it. An STL or OBJ only lets us measure thicknesses, access and slots.
Preparing the analysis…
Reading the file…
Converting the STEP in our CAD service…
Loading the example part…
Reading the mesh…
Separating the faces of the STEP…
Measuring thicknesses and access…
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The analysis reads STEP and STP. An STL or an OBJ as well, but only for a partial analysis.
The file is empty.
The STEP file exceeds 10 MB. Remove unnecessary details for manufacturing or upload the part directly to the quoting platform.
The file exceeds 60 MB. Export it with lower resolution or in STEP format, which takes up much less space.
The file is not a valid STEP. Re-export it from your CAD software.
The file contains no solids: it may only contain surfaces or a 2D drawing.
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The analysis took too long. If the part is very complex, simplify it or request the quote directly.
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Can't be machined
As it is, it won't come off the machine.
A single point prevents it.
points prevent it.
Another one complicates it.
more complicate it.
Click each one to view it on the part.
Can be machined
Can be machined, with care.
One point makes the part more expensive or puts it at risk. Check it before ordering.
points make the part more expensive or put it at risk. Check them before ordering.
Ready to machine
Nothing that complicates it.
We see no radii, thicknesses, holes or access beyond what's reasonable.
No visible issues
Nothing that complicates it, as far as we can see.
With a mesh we only check thicknesses, access and slots. Upload the STEP for the full analysis.
Sample part
faces
mesh without the STEP faces
turned part
one working side ()
working sides ()
No machining issues.
Nothing matches the selected filters.
What to do
Internal corners
Internal radii
Drilled holes
Walls
Access and undercuts
Slots and pockets
Protrusions
Enclosed cavities
Bodies
Entire part
Turning
mm
mm
Aluminum
steel
plastic
Through hole Ø
Blind hole Ø
Internal hole Ø
mm long · × Ø
At Ø mm it's below the Ø minimum: no drill will hold up.
Enlarge the hole to Ø mm or more, or ask for it to be made by EDM or laser.
A Ø mm hole is small: the drill breaks or wanders easily.
In steel, a Ø mm hole is small: the drill breaks or wanders easily.
If it is not functional, change it to Ø mm or more.
Depth of × Ø: beyond × Ø it takes a long drill with through-tool coolant, because chips build up at the bottom.
If you can, leave it at mm or make it a through hole.
Depth of × Ø: the maximum is × Ø.
Shorten it to mm or make it a through hole.
Depth of × Ø: through holes have no depth warning up to × Ø. Beyond that, a long drill with through-tool coolant is required.
If the function allows, shorten it.
Depth of × Ø: it exceeds the × Ø maximum and has to be drilled from both sides, with the risk that the two halves don't line up.
If possible, widen it or shorten it below mm.
Depth of × Ø: even drilling from both sides won't reach; the maximum is × Ø.
Shorten it or widen it.
The axis is inclined relative to the part's faces.
Request an inclined setup or 5-axis machining; if possible, align it with a face.
The drill enters a face inclined at °: it touches with only one cutting lip, slips and breaks.
The drill enters a face inclined at ° and tends to slip.
Add a perpendicular flat at the entry, a Ø spot face.
It exits through a face inclined at °.
The drill wanders as it breaks through: add a flat exit face.
It cuts into the edge of the part: only ° of the circumference is inside the material.
Leave at least three-quarters of the hole inside the material, or convert it into a milled slot.
Flat bottom at × Ø: the drill leaves a point, and a Ø end mill won't reach that deep.
Flat bottom at × Ø: the drill leaves a point, and it has to be finished with a long end mill.
Flat bottom: the drill leaves a point, and it has to be finished with an end mill.
Does it have to be flat? If not, leave the drill's 118° point.
Round bottom at × Ø: the drill leaves a point, and a Ø ball-end mill won't reach that deep.
Round bottom at × Ø: the drill leaves a point, and it has to be finished with a long ball-end mill.
Round bottom: the drill leaves a point, and it has to be finished with a ball-end mill.
Does it have to be round? If not, leave the drill's 118° point.
Pointed bottom of °: a standard drill leaves a 118° to 140° point, and any other angle needs a different tool or finishing with an end mill.
Pointed bottom of ° at × Ø: a standard drill leaves a 118° to 140° point, and at that depth any other angle needs a custom-ground drill.
Does it have to be °? If not, leave the drill's 118° point.
Ø is not a standard drill diameter: it is made with an end mill, by interpolation, or with a reamer.
If it is not a fit, change it to Ø.
Ø is the tap drill for an M thread.
Ø is the tap drill for an M thread, below M3, the smallest our guide covers.
If it is a thread, indicate it in the PDF: the 3D model does not include it.
Intersecting holes · Ø and Ø
at 90° and centered
angle of °
The intersection is well laid out, but it leaves a burr inside that has to be removed by hand.
If the inside is functional, such as a bearing or seal seat, say so and we'll plan the deburring.
When it reaches the intersection, the drill loses support on one side and wanders. It also leaves a burr inside that has to be removed by hand.
When it reaches the intersection, the drill loses support on one side and wanders, all the more with two diameters this similar. It also leaves a burr inside that has to be removed by hand.
Make the axis of the smaller hole pass through the center of the larger one. If the intersection isn't functional, separate them.
Make the axis of the smaller hole pass through the center of the larger one, ideally one twice its diameter. If the intersection isn't functional, separate them.
Overlapping holes · Ø and Ø
axes mm apart
They overlap side by side: when drilling the second one, the drill loses support over ° of its turn and wanders toward the first.
Space the axes at least mm apart. If they have to touch, draw them as a slot: it's milled in one go.
They overlap side by side, but only slightly: drilled in the right order, the second one only lacks support over ° of its turn.
If one of the two is a fit, such as a bearing seat, mark it: it's machined last.
Inner radius R
Inner radius R · corners
mm deep
The end mill leaves its own radius in vertical corners. This one calls for a Ø end mill working mm deep, times its diameter, and in the maximum is times.
The end mill leaves its own radius in vertical corners, and a radius under 1 mm calls for a very thin end mill.
The end mill leaves its own radius in vertical corners, and this one is less than a third of the depth: the end mill has to be long and thin.
Increase it to R or more: R ≥ depth / 3, and never less than 1 mm.
The end mill leaves its own radius in vertical corners. This one calls for a Ø end mill working mm deep, times its diameter: it needs a long-reach end mill, which cuts more slowly.
Increase it to R or more: the end mill works shorter and faster.
Sharp internal corner
Sharp internal corners ·
mm height
An end mill rotates: in a vertical internal corner it always leaves its radius. A sharp corner can only be made by EDM.
Add a radius of at least mm, or a corner relief if another part fits there.
Thin wall of mm
minimum mm in metal
minimum mm in plastic
At mm the wall gives way under the end mill's push: it vibrates, leaves a poor finish and may change size once unclamped.
Increase it to mm or more, or shorten its free height.
Internal groove in a hole
Internal grooves in holes ·
Area only reachable with 5 axes
Areas only reachable with 5 axes ·
Undercut without direct access
Undercuts without direct access ·
mm² surface area
A drill can't reach a groove inside the hole: it's made with an end mill or a grooving tool, which need a minimum hole diameter to get in.
None of the six faces of the part provides direct access to this area. A 5-axis machine can reach it by tilting the tool.
This surface is hidden behind another: a straight end mill cannot reach it from any direction.
If it's for a seal, give its reference in the PDF.
If possible, orient the area towards a face of the part.
Open it towards a face, give it the dimensions of a T-slot or dovetail cutter, or split the part.
Narrow slot of mm
Narrow slots ·
Deep pocket of mm
Deep pockets ·
mm depth · × width
the worst: mm wide and deep · × width
The end mill cannot be wider than the slot. With mm width and depth, it must be long and thin: it will flex, vibrate, and get clogged with chips.
To reach the bottom, an end mill times longer than the pocket width is required.
To reach the bottom of the deepest one, an end mill times longer than its width is required.
Widen it to mm or leave it at mm depth.
Reduce the depth or open the pocket: the recommended depth is up to times the width.
Slender protrusion Ø
Thin protrusion Ø
mm height · × Ø
A tall, thin pin flexes under the end mill's push: it bends or snaps during finishing.
At Ø mm the pin barely withstands the end mill's push as it goes around it.
Thicken it to Ø mm or more, or use a press-fit pin instead.
Thicken or shorten it to × Ø, or use a press-fit pin instead.
Are the units correct?
The part measures less than one millimeter: the file was likely exported in other units.
The part measures more than three meters: the file was likely exported in other units.
Re-export the STEP in millimeters.
Very small part
Below × mm, there is almost no room to hold it: it is machined attached to a block and separated at the end.
If you need several identical ones, order them together: they come out of the same bar.
Surfaces requiring 3D milling
% of the surface
Faces that aren't planes, cylinders or cones are milled in 3D with a ball-nose end mill and very closely spaced passes: machine time multiplies, and it often needs 5 axes.
If the shape is not functional, replace it with planes, fillets, and chamfers.
Enclosed cavity inside the part
No tool can reach a cavity with no opening to the outside.
Open it towards a face or split the part into two pieces screwed together.
More than one body in the file
The file contains loose parts. Each part goes in its own file.
Export each body separately.
Slender turned part
mm long · Ø · × Ø
A long, thin part flexes under the cutting tool's push: it comes out barrel-shaped and chatters. Beyond times the diameter it has to be turned between centers.
A long, thin part flexes under the cutting tool's push: it comes out barrel-shaped and chatters. Beyond times the diameter it has to be turned between centers, and beyond , with a steady rest.
If you can, shorten or thicken it; if not, say so and we'll plan a tailstock or a steady rest.
Partial analysis
With a mesh we can't tell what each face is: we don't check radii, sharp corners, holes or pins. Thicknesses, access and slots, yes.
Upload the STEP for the complete analysis.
Machined from sides
Each side is one more setup: clamping, repositioning and referencing the part all over again. Normally it's done in one or two.
If possible, orient the drilled holes and pockets toward fewer faces.
- Dragrotates
- Wheelzooms, after clicking the part
- Right-clickpans
- Double-clickcenters there
- Click a markexplains the problem
- One fingerrotates
- Pinchzooms
- Two fingerspan
Your file is not stored. The STEP file is sent encrypted to our CAD analysis server, which converts it to a mesh and then discards it; the rest of the analysis runs in your browser. STL and OBJ files never leave your computer. Only want to measure or weigh it? Open it in the STEP viewer
01 / What it checks
What a CNC programmer
looks at.
We look for what forces a change of tool, setup or machine, which is what makes a part expensive, and for what no end mill can do.
Internal corners
The end mill rotates and leaves its radius in every vertical corner. We check how deep the end mill that cuts it has to go: no warning up to 10 times its diameter in aluminum. A 12 mm deep pocket can be made with R1; with R4 the end mill is thicker and cuts faster. A sharp corner can only be made by EDM.
Thicknesses
We measure the thickness of every area of the part. Below 0.8 mm in metal, or 1.5 mm in plastic, the wall vibrates under the end mill's push. Below 0.5 mm in metal it doesn't hold up.
Diameter, depth, and entry
For blind holes, L ≤ 6 × D is the recommended depth with a standard drill. The maximum in this guide is 20 × D, with a long drill and through-tool coolant. Through holes get no depth warning up to 9 × D; from 20 to 40 × D they are drilled from both sides. Minimum diameter: 0.5 mm.
Slots, pockets, and undercuts
From every point on the surface we check whether a straight end mill reaches it from any of the six sides. If it can't, even tilting the tool on 5 axes, it is an undercut. And we measure the depth of each slot against its width.
02 / Frequently asked questions
Design for milling,
what we're asked about most.
Eleven short answers. The rest, in the frequently asked questions.
View all questionsWhat is a manufacturability check (DFM)?
It involves reviewing a design with manufacturing in mind: DFM stands for Design for Manufacturing. In machining, it means identifying what a milling cutter cannot do or makes expensive, such as sharp corners, thin walls, very deep drilled holes, narrow slots, and areas where the tool cannot reach.
Is the analysis free? Do I need to register?
It's free, with no registration. We built it so you can fix the part before asking for a quote, which is when changing it costs nothing.
Is my file saved?
No. The STEP travels encrypted to our CAD analysis server, which converts it into a mesh and discards it when it's done; the rest of the analysis runs in your browser. STL and OBJ files never leave your computer. Nor is the file added to any quote request.
Why is the analysis partial with an STL?
Because an STL only stores triangles: it doesn't say where a hole ends and a radius begins. With it we measure thicknesses, access and slots. To check radii, sharp corners, holes and pins we need the STEP, which keeps every face exactly as you drew it.
How deep can a drilled hole be?
For blind holes, L ≤ 6 × D is the recommended depth with a standard drill. The maximum in this guide is 20 × D, with a long drill and through-tool coolant. Through holes get no depth warning up to 9 × D; from 20 to 40 × D they are drilled from both sides. Minimum diameter: 0.5 mm.
What minimum internal radius does a pocket need?
Never less than 1 mm. Above that, what matters is the reach of the end mill that cuts the corner: no warning up to 10 times its diameter in aluminum, 6 in steel and 12 in plastic. A 12 mm deep pocket can be made with R1; with R4 the end mill is thicker and cuts faster. A sharp internal corner can only be made by EDM.
What is the minimum wall thickness that can be milled?
0.8 mm in metal and 1.5 mm in plastic. Below these values, the wall yields to the milling cutter's thrust: it vibrates, leaves a poor finish, and may change size once unclamped. Below 0.5 mm in metal, or 1 mm in plastic, we mark it in red.
What do I do if my part comes up in red?
Click each mark: we tell you why it can't be done and what to change, with the figure. If that shape is needed for the part to work, request the quote anyway and say so: sometimes it's solved with EDM, with 5 axes or by splitting the part.
Why do the warnings change with the material?
Because steel needs shorter end mills and plastic gives way more. In this guide, an end mill works without a warning up to 6 times its diameter in steel, 10 in aluminum and 12 in plastic. The general drilling depth limits are the same in all three materials. In plastic, the minimum wall rises from 0.8 to 1.5 mm.
Does it work for turned parts?
It recognizes parts of revolution and reviews their slenderness: beyond 6 times the diameter, they must be turned between centers, and beyond 12, with a steady rest. Grooves and deep interiors are reviewed when preparing the quote.
Does it replace an engineer's review?
No. It is an automatic, indicative analysis that catches the usual issues. When preparing the quote, our engineering team reviews each part with its drawing and tolerances.
Design ready?
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