MACHINING OF METALS AND PLASTICS
CNC Drilling
TECHNOLOGICAL CONSULTING | INDUSTRIAL PRODUCTION | ENGINEERING SERVICES
CNC drilling means producing holes on numerically controlled machines – from through and blind holes, through deep-hole drilling, to precision holes held to a specified tolerance. Below you will find the scope of what we can do.
MDP Precision performs CNC drilling both as a stand-alone service and as part of the complete machining of a part. We drill on vertical and horizontal machining centres and on CNC lathes, which allows the holes to be produced in a single setup together with turning and milling – with no re-fixturing and no loss of positional accuracy.
We operate a modern machine park: from the 5-axis DN Solutions DVF 5000 (Ø650 mm table, A/C tilt and rotation 140°/360°) and DMG MORI CMX 70 U, through DN Solutions DNM 750 II vertical centres with travels of 1630 × 762 × 650 mm and a table load capacity of 1500 kg, to the PUMA GT3100LM lathe (turning up to Ø376 mm over a length of 1245 mm) and the LYNX 2100LYA with Y and C axes. This lets us drill holes at an angle and in axes that are not parallel to the datum, for single pieces as well as series production.
What types of holes do we produce in CNC drilling?
THROUGH AND BLIND HOLES: drilled from solid on machining centres and CNC lathes, in parts up to 1630 × 762 × 650 mm and 1500 kg. Spindles running up to 15,000 rpm also allow small-diameter holes in aluminium and engineering plastics.
DEEP-HOLE DRILLING: holes whose depth is a multiple of their diameter, produced with long tools, coolant supply and controlled chip evacuation. On the MIUMAC DF1840-E lathe we machine shafts up to 1500 mm long, which also allows long axial holes.
PRECISION HOLES – REAMING AND BORING: drilling alone gives the accuracy typical of the method, usually IT11–IT12. Where the drawing calls for a fit, we ream or bore the hole – as standard to H7/H8 and a surface finish of around Ra 1.6–3.2 µm. The final level is confirmed after reviewing the drawing.
TAPPING, COUNTERBORING AND CHAMFERING: after drilling we carry out CNC threading, cylindrical and conical counterbores and chamfers – within the same machining cycle. Driven tools in the lathes (up to 5,000 rpm) and the Y and C axes of the LYNX 2100LYA allow cross drilling and tapping without re-clamping the part.
THE CNC DRILLING PROCESS
DRAWING REVIEW: we check tolerances, depths and the relative position of the holes, and point out places where a small design change will reduce the cost of the part.
PROGRAMMING AND TOOL SELECTION: we prepare the CAM program and select the drills and cutting parameters to suit the material and the proportions of the hole.
MACHINING AND INSPECTION: we drill and then measure hole diameters, depths and spacing.
We work within a quality management system confirmed by an ISO certificate, and every batch of parts undergoes dimensional inspection. Holes are checked for diameter, form and position tolerance and surface finish, and the measurement results are documented. Thanks to this our parts are accepted without reservations in the most demanding industries – automotive, aerospace, pharmaceutical, marine and defence.
Frequently asked questions about CNC drilling
The quickest way is a 2D drawing or 3D model with tolerances, material and quantity marked. After reviewing the documentation we come back with a quotation and a proposed technology; for more complex parts we first ask about tolerances and the intended use – this often makes it possible to reduce cost without affecting function.
We drill in structural and tool steels, stainless and acid-resistant steels, aluminium, copper, brass, titanium and engineering plastics. Tools and cutting parameters are selected individually for each material.
We handle prototypes and single parts as well as series production. For larger batches we prepare the workholding and optimise the cycle, which lowers the unit cost of the part.
Yes. Threading, counterboring and chamfering are carried out within the same machining cycle, in a single setup. As a result the thread is perpendicular to the face and the relative position of the holes stays true to the drawing.
We speak of deep-hole drilling when the depth of the hole is a multiple of its diameter. It requires tools with coolant supplied through the tool, carefully selected parameters and controlled chip evacuation – otherwise the hole drifts off axis and the tool quickly loses its cutting ability.
Drilling alone gives accuracy of around IT11–IT12. If the drawing calls for a fit, we additionally ream or bore the hole, reaching H7/H8 classes with a surface finish of around Ra 1.6–3.2 µm. The final tolerance and finish are confirmed after reviewing the drawing and the material, and the dimensions are recorded in our inspection report.
We match the diameter range to the part and the material – from small holes in aluminium and plastics (spindles running up to 15,000 rpm) to large bores produced by boring. In practice the size of the part matters more than the hole itself: on machining centres we work with parts up to 1630 × 762 × 650 mm and 1500 kg, and on lathes with shafts up to Ø530 mm and 1500 mm long. For deep holes the decisive factor is the depth-to-diameter ratio – with unusual proportions we confirm feasibility from the drawing.
CNC drilling is used wherever holes have to be repeatable and held to a specified tolerance. Most often we produce them in the following groups of parts.
HOUSINGS AND ENCLOSURES
They require dozens of mounting and threaded holes in exact relative positions – we drill them in a single setup.
PLATES AND FIXTURE BASES
Fitted, threaded and dowel holes that determine the repeatability of the entire fixture.
FLANGES AND CONNECTING PARTS
Bolt holes arranged on a pitch circle, produced in series while holding the spacing tolerance.
HYDRAULIC AND PNEUMATIC COMPONENTS
Long through holes and galleries, often intersecting, with threaded connection ports.
SHAFTS WITH OIL GALLERIES
Deep holes drilled along or at an angle to the axis, feeding oil to bearings and mating surfaces.
BUSHINGS AND GUIDE ELEMENTS
Reamed and bored holes held to a tight tolerance, for bearings, pins and guides.
FIXTURES AND MOULDS
Holes for ejectors, cooling channels and locating elements that require exact positioning.
WELDED STRUCTURES
Mounting holes in components that we then join in our welding shop – one process, one supplier.
