Milling centre Cologne · Telescopic and hybrid manufacturing
Telescopic work milled to order: retention that still holds after the 50th removal
CADmill is a milling centre in Cologne, Germany. 17 years in the market, more than 24,000 secondary structures per year. Before you send out your next telescopic case: ask us and your current supplier the same five questions.
Why the mating surface alone decides a telescopic case
You know the moment at the fitting stage. The secondary part slides onto the primary part, and within two seconds you know how the case will go. Does it seat cleanly, does it hold without binding, does it release under control? Or does it sit too loose and you are already thinking about how to explain that to the dentist?
With crowns and bridges you have a margin. The cement gap forgives a few microns. With a telescope nothing forgives anything. Retention comes solely from the pairing of primary and secondary part. A milled mating surface cannot be reactivated the way a spring attachment can. What comes off the machine is the fit. Everything else is rework.
And the rework lands with you, not with the milling centre. If the patient says after six months that the denture no longer holds, they call the practice. The practice calls you. You carry the chair time, the shipping, the remake and your reputation with that dentist.
Even so, most laboratories compare milling centres by price per unit and delivery time. Both describe a supplier’s logistics. Neither says anything about process control. Retention is not created in the quotation. It is created in the chain of machine, room temperature, tool condition and measurement. And that chain is something a supplier either shows you or does not.
What controls friction in our production
Parallel mating surfaces as standard, a taper on request
We mill telescopic work with parallel-walled mating surfaces. Friction is built up evenly along the entire insertion path instead of engaging only near the final seat. For your cases that means predictable retention, including on multi-unit frameworks.
A conical mating surface is milled on request. A taper is useful with a limited mouth opening, with diverging abutments, or when your concept calls for a defined removal behaviour via the taper angle. Simply state parallel surface or taper when you place the order, and for a taper the angle you want. Both variants run through the same process chain: air-conditioned production, monitored machine accuracy, mating surface machined last.
Temperature in the milling room
When a batch fits differently in January than in July, the data set is rarely the reason. Workpiece, tool and machine expand with temperature. On parallel mating surfaces in the single-digit micron range that is the difference between a snug fit and play. Our production rooms are therefore air-conditioned.
Industrial-grade machines with continuously monitored accuracy
We run industrial-grade CNC machines and monitor their accuracy using laser and magnetic technology. Not only when a case becomes conspicuous, but as a fixed part of daily operation. A machine that drifts by a few microns keeps producing parts. It just stops producing retention.
Hybrid manufacturing: the mating surface is milled last
We combine additive and subtractive steps in processes we use exclusively. The base body is built up additively, the mating surface is then machined. Your fit therefore does not depend on a printing or casting result, but on the geometry milled last. More on this under production processes.
Laser sintering on Trumpf systems
The additive step runs on laser sintering systems from Trumpf. We deliberately keep the equipment up to date, because a consistent sintering result is the precondition for the subsequent milling operation to work reproducibly at all. Where we have to choose between cheaper and dependable equipment, we choose the technology that carries the result.
Repetition on exactly this geometry
More than 24,000 secondary structures per year, 17 years in the market. We know how our tools wear on telescopic mating surfaces, not on crown copings. That is the part you cannot buy.
You do not have to take our word for it. Ask. Ask us, and ask every other supplier on your list.
Friction elements and bar constructions
Friction elements on request. Retention does not have to come from the mating surface alone. On request we fit precise friction elements into the secondary crown, for example systems from Sitec or comparable elements. This is particularly useful on short abutments, with a short mating surface, or when you want an activatable friction element inside the part instead of relying solely on the mating surface. State the system you want with the order and we will allow for its seat and position at the design stage.
Bar constructions from the same process. The hybrid system is not limited to telescopes. We produce bar constructions in the same workflow: base body sintered additively, mating surfaces and seats machined last. The bar therefore goes through the same process chain as the secondary crown, including air-conditioned production and monitored machine accuracy.
Checklist for your next milling centre conversation
-
“Do you measure friction, or do you just mill it?”
Ask to see what comes back with the case: actual parallelism and wall angle, removal force, result after a defined number of insertion cycles. A machine data sheet is not a measurement on your part. -
“After how many parts do you change the cutter, and where is that recorded?”
A blunt tool does not visibly mill worse, it keeps milling. That is exactly why the last parts in a batch sometimes seat more loosely than the first. Anyone who cannot state a tool life limit per tool and material is changing cutters by feel. -
“Do CoCr, titanium and zirconia run on separate machining lines?”
Foreign particles on a mating surface are not a cosmetic issue. They leave score marks on the mating surface and the fit shifts with every insertion. Ask about physical separation, not about the cleaning routine. -
“Who pays for the remake if retention drops after six months?”
This question separates suppliers more reliably than any brochure. Get the arrangement in writing, with a time limit and a defined scope. Otherwise you carry the case alone. -
“Who do I reach at 4:40 pm when the case has to ship tomorrow?”
With telescopes the decisive step is the query before milling: wall thickness, cutter limits, undercuts, parallelism or taper angle. A centre that quietly mills an implausible data set delivers scrap with a delivery note.
Ask us those five questions too: +49 221 69065728.
Sales claim versus verifiable commitment
| What you hear in the conversation | What you should ask for instead |
|---|---|
| “We mill on five axes.” | The actual dimension on the delivered secondary part. The number of axes describes the machine, not your case. |
| “Our accuracy is in the micron range.” | Measured on what, with what, how often? Without a record that is a number from a leaflet. |
| “We process certified materials.” | A certificate describes the blank. What you have to fit is the surface created afterwards. |
| “We handle complaints generously.” | Goodwill is not an arrangement. Time limit, scope and responsibility in writing. |
| “You can reach us any time.” | The name of the person who actually sees your cases, and their direct line. |
The comparison case: measure instead of trust
Recommendations are no substitute for measurement. Send us the same data set your current supplier receives. A case with four abutments, primary and secondary parts, is the most informative. Then put both deliveries side by side and check: actual fit dimensions, surface quality of the mating surface, removal force before and after 50 insertion cycles. After that you decide with numbers instead of gut feeling.
Shipping routes, collection and production times are listed under service. You can upload design data or send in models.
Terms that come up in the milling centre conversation
- Friction / retention
- The hold that comes solely from the friction between primary and secondary part. Too little means a loose denture, too much means the patient cannot remove it.
- Removal force
- The force needed to release the secondary part from the primary part, measured in newtons. The only value that turns retention into a comparable number.
- Parallel surface
- The parallel-walled mating surface between primary and secondary part. It creates friction along the entire insertion path and is the CADmill standard for telescopic work.
- Taper angle
- The opening angle of a conical mating surface. A few tenths of a degree away from the target value change the removal force noticeably, especially on short abutments. Conical mating surfaces are milled on request.
- Insertion cycle
- One complete seating and removal. A cycle test shows whether retention remains after repeated use or already drops in the laboratory.
- Secondary structure
- The part that goes over the primary part, single or splinted. More than 24,000 of them per year at CADmill.
- Friction element
- A component fitted into the part that creates or supplements the hold between primary and secondary part, for example systems from Sitec. We fit them into the secondary crown on request.
- Bar construction
- A connecting bar between abutments or implants that guides the denture. We produce it in the same hybrid workflow as secondary structures.
- Tool life
- The number of parts a cutter is allowed to machine before it is replaced. Without a defined limit the fit drifts within a batch.
- Hybrid manufacturing
- Additive and subtractive steps in one workflow. The base body is built up, the mating surface is milled last.
Frequently asked questions about outsourcing telescopic work
Do you work with parallel surfaces or with a taper on telescopic work?
Parallel mating surfaces are the standard: we mill telescopic work with parallel-walled surfaces because friction is then built up evenly along the entire insertion path. A conical mating surface is produced on request, in which case please state the taper angle with the order.
Why is telescopic work more demanding than crowns and bridges?
Because no cement compensates for tolerance. Retention arises solely from the pairing of primary and secondary part. Deviations in the micron range on the mating surface change the removal force noticeably.
How do I recognise a milling centre that has telescopic work under control?
By five answers. It measures friction and encloses a record. It knows its tool life figures and documents cutter changes. It separates the machining of CoCr, titanium and zirconia. It states in writing who covers the remake if retention drops. And it puts a technician on the phone who knows the case.
Can milled secondary parts be reactivated later?
Not the way a spring attachment or a cast telescopic crown can. A mating surface is a surface, not a spring element. That is why retention has to be right out of production, not out of rework in the laboratory.
Why does room temperature matter in production?
Workpiece, tool and machine expand with temperature, so temperature drift becomes dimensional drift. With mating surfaces in the single-digit micron range, air-conditioned production is the precondition for a case fitting in summer the way it fits in winter.
What does hybrid manufacturing mean for telescopes?
Additive and subtractive steps are combined. The base body is produced additively, the mating surfaces are then machined. The decisive surface therefore does not lie in the printing or casting result, but in the geometry milled last. CADmill uses its own processes for this.
How do I compare two milling centres objectively?
With the same data set to both suppliers. Then measure the two deliveries against each other: actual fit dimensions, surface quality and removal force before and after 50 insertion cycles. That replaces any recommendation.
Which materials are suitable for primary and secondary parts?
CoCr, titanium and zirconia are common, and depending on the concept high-performance polymers as well. You will find an overview of our material range under production processes.
What happens if my data set cannot be produced as designed?
Then we call you before the machine starts. Wall thicknesses that are too thin, undercuts, or angles that cannot be produced cleanly with the selected tool are clarified with you beforehand. A part milled from a faulty data set helps nobody.
Can you fit friction elements into the secondary crown?
Yes, on request. We fit precise friction elements, for example systems from Sitec or comparable ones. Name the system when you place the order so that seat and position are allowed for at the design stage.
Do you also produce bar constructions?
Yes, in the same hybrid system as the secondary structures: base body sintered additively, mating surfaces and seats milled last.
What equipment do you produce on?
The additive step is sintered on laser sintering systems from Trumpf. Machining runs on industrial-grade CNC machines whose accuracy we monitor with laser and magnetic technology, in air-conditioned rooms.
Where is CADmill located and how do I reach production?
CADmill is a milling centre in Cologne, Germany, Steinweg 23, 51107 Cologne. 17 years in the market, more than 24,000 secondary structures per year. Phone +49 221 69065728, e-mail info@cadmill.de.
How to start
Call us: +49 221 69065728. Or write to info@cadmill.de, subject “telescopic comparison case”. We clarify the case technically before a machine starts: parallel surface or taper, gap, material pairing. Then we mill. All contact options are listed under contact.